Mira

Mira (), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red giant star estimated to be 200–400 light-years from the Sun in the constellation Cetus.
ο Ceti is a binary stellar system, consisting of a variable red giant (Mira A) along with a white dwarf companion (Mira B). Mira A is a pulsating variable star and was the first non-supernova variable star discovered, with the possible exception of Algol. It is the prototype of the Mira variables.
Nomenclature.
ο Ceti (Latinised to "Omicron Ceti") is the star's Bayer designation. It was named Mira (Latin for 'wonderful' or 'astonishing') by Johannes Hevelius in his "Historiola Mirae Stellae" (1662). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included Mira for this star.
Observation history.
Evidence that the variability of Mira was known in ancient China, Babylon or Greece is at best only circumstantial. What is certain is that the variability of Mira was recorded by the astronomer David Fabricius beginning on August 3, 1596. Observing what he thought was the planet Mercury (later identified as Jupiter), he needed a reference star for comparing positions and picked a previously unremarked third-magnitude star nearby. By August 21, however, it had increased in brightness by one magnitude, then by October had faded from view. Fabricius assumed it was a nova, but then saw it again on February 16, 1609.
In 1638 Johannes Holwarda determined a period of the star's reappearances, eleven months; he is often credited with the discovery of Mira's variability. Johannes Hevelius was observing it at the same time and named it Mira in 1662, for it acted like no other known star. Ismail Bouillaud then estimated its period at 333 days, less than one day off the modern value of 332 days. Bouillaud's measurement may not have been erroneous: Mira is known to vary slightly in period, and may even be slowly changing over time. The star is estimated to be a six-billion-year-old red giant.
There is considerable speculation as to whether Mira had been observed prior to Fabricius. Certainly Algol's history (known for certain as a variable only in 1667, but with legends and such dating back to antiquity showing that it had been observed with suspicion for millennia) suggests that Mira might have been known too. Karl Manitius, a modern translator of Hipparchus' "Commentary on Aratus", has suggested that certain lines from that second-century text may be about Mira. The other pre-telescopic Western catalogs of Ptolemy, al-Sufi, Ulugh Beg, and Tycho Brahe turn up no mentions, even as a regular star. There are three observations from Chinese and Korean archives, in 1596, 1070, and the same year when Hipparchus would have made his observation (134 BC) that are suggestive.
Distance.
The distance to Mira is uncertain; pre-Hipparcos estimates centered on 220 light-years; while Hipparcos data from the 2007 reduction suggest a distance of 299 light-years, with a margin of error of 11%.
Stellar system.
This binary star system consists of a red giant (Mira, designated Mira A) undergoing mass loss and a high temperature white dwarf companion (Mira B) that is accreting mass from the primary. Such an arrangement of stars is known as a symbiotic system and this is the closest such symbiotic pair to the Sun. Examination of this system by the Chandra X-ray Observatory shows a direct mass exchange along a bridge of matter from the primary to the white dwarf. The two stars are currently separated by about 70 astronomical units.
Component A.
Mira A is currently an asymptotic giant branch (AGB) star, in the thermally pulsing AGB phase. Each pulse lasts a decade or more, and an amount of time on the order of 10,000 years passes between each pulse. With every pulse cycle Mira increases in luminosity and the pulses grow stronger. This is also causing dynamic instability in Mira, resulting in dramatic changes in luminosity and size over shorter, irregular time periods.
The overall shape of Mira A has been observed to change, exhibiting pronounced departures from symmetry. These appear to be caused by bright spots on the surface that evolve their shape on time scales of 3–14 months. Observations of Mira A in the ultraviolet band by the Hubble Space Telescope have shown a plume-like feature pointing toward the companion star.
Variability.
Mira A is a variable star, specifically the prototypical Mira variable. The 6,000 to 7,000 known stars of this class are all red giants whose surfaces pulsate in such a way as to increase and decrease in brightness over periods ranging from about 80 to more than 1,000 days.
In the particular case of Mira, its increases in brightness take it up to about magnitude 3.5 on average, placing it among the brighter stars in the Cetus constellation. Individual cycles vary too; well-attested maxima go as high as magnitude 2.0 in brightness and as low as 4.9, a range almost 15 times in brightness, and there are historical suggestions that the real spread may be three times this or more. Minima range much less, and have historically been between 8.6 and 10.1, a factor of four times in luminosity. The total swing in brightness from absolute maximum to absolute minimum (two events which did not occur on the same cycle) is 1,700 times. Mira emits the vast majority of its radiation in the infrared, and its variability in that band is only about two magnitudes. The shape of its light curve is of an increase over about 100 days, and the return to minimum taking twice as long.
Contemporary approximate maxima for Mira:
From northern temperate latitudes, Mira is generally not visible between late March and June due to its proximity to the Sun. This means that at times several years can pass without it appearing as a naked-eye object.
The pulsations of Mira variables cause the star to expand and contract, but also to change its temperature. The temperature is highest slightly after the visual maximum, and lowest slightly before minimum. The photosphere, measured at the Rosseland radius, is smallest just before visual maximum and close to the time of maximum temperature. The largest size is reached slightly before the time of lowest temperature. The bolometric luminosity is proportional to the fourth power of the temperature and the square of the radius, but the radius varies by over 20% and the temperature by less than 10%.
In Mira, the highest luminosity occurs close to the time when the star is hottest and smallest. The visual magnitude is determined both by the luminosity and by the proportion of the radiation that occurs at visual wavelengths. Only a small proportion of the radiation is emitted at visual wavelengths and this proportion is very strongly influenced by the temperature (Planck's law). Combined with the overall luminosity changes, this creates the very big visual magnitude variation with the maximum occurring when the temperature is high.
Infrared VLTI measurements of Mira at phases 0.13, 0.18, 0.26, 0.40, and 0.47, show that the radius varies from at phase 0.13 just after maximum to at phase 0.40 approaching minimum. The temperature at phase 0.13 is and at phase 0.26 about halfway from maximum to minimum. The luminosity is calculated to be at phase 0.13 and at phase 0.26.
The pulsations of Mira have the effect of expanding its photosphere by around 50% compared to a non-pulsating star. In the case of Mira, if it was not pulsating it is modelled to have a radius of only around .
Mass loss.
Ultraviolet studies of Mira by NASA's Galaxy Evolution Explorer (GALEX) space telescope have revealed that it sheds a trail of material from the outer envelope, leaving a tail 13 light-years in length, formed over tens of thousands of years. It is thought that a hot bow-wave of compressed plasma/gas is the cause of the tail; the bow-wave is a result of the interaction of the stellar wind from Mira A with gas in interstellar space, through which Mira is moving at an extremely high speed of 130 kilometres/second (291,000 miles per hour). The tail consists of material stripped from the head of the bow-wave, which is also visible in ultraviolet observations. Mira's bow-shock will eventually evolve into a planetary nebula, the form of which will be considerably affected by the motion through the interstellar medium (ISM).
Component B.
The companion star was resolved by the Hubble Space Telescope in 1995, when it was 70 astronomical units from the primary; and results were announced in 1997. The HST ultraviolet images and later X-ray images by the Chandra space telescope show a spiral of gas rising off Mira in the direction of Mira B. The companion's orbital period around Mira is approximately 400 years.
In 2007, observations showed a protoplanetary disc around the companion, Mira B. This disc is being accreted from material in the solar wind from Mira and could eventually form new planets. These observations also hinted that the companion was a main sequence star of around 0.7 solar masses and spectral type K, instead of a white dwarf as originally thought. However, in 2010 further research indicated that Mira B is, in fact, a white dwarf.


9 Pegasi

9 Pegasi (9 Peg) is a supergiant star in the constellation Pegasus. Its apparent magnitude is 4.35.
9 Pegasi is defined and used as an MK standard star for the spectral type G5 Ib. It is a yellow supergiant nearly two thousand times more luminous than the sun and sixty times larger. It has been reported to be slightly variable and is listed in the New Catalogue of Suspected Variable Stars with a magnitude range of 4.20 to 4.35.
9 Pegasi does not have a Bayer designation although it is brighter than several stars in Pegasus that do such as τ, φ, and σ Pegasi. It is the 9th star numbered by Flamsteed in order of right ascension. In the 1795 French-language Fortin-Flamsteed edition of the Atlas Coelestis, 9 Pegasi is labelled with the letter "g".


NGC 3259

NGC 3259 is a barred spiral galaxy located approximately 90 million light-years from Earth, in the Ursa Major constellation. It has the morphological classification SAB(rs)bc, which indicates that it is a spiral galaxy with a weak bar across the nucleus (SAB), an incomplete inner ring structure circling the bar (rs), and moderate to loosely wound spiral arms (bc). This galaxy is a known source of X-ray emission and it has an active galactic nucleus of the Seyfert 2 type.


HR 6875

HR 6875, previously known as Sigma Telescopii, is a single star in the constellation Corona Australis. It has a blue-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.24. This object is located at a distance of approximately 550 light years from the Sun based on parallax. It is listed as a member of the Sco OB2 association.
This is a hot B-type main-sequence star with a stellar classification of B3 V. It is around 103 million years old and is spinning rapidly with a projected rotational velocity of 248 km/s or perhaps higher. The star has six times the mass of the Sun and about four times the Sun's radius. It is radiating more than a thousand times the luminosity of the Sun from its photosphere at an effective temperature of 20,350 K.
A magnitude 10.13 visual companion is located at an angular separation of along a position angle of 162°.


59 Cygni

59 Cygni is a multiple star system in the northern constellation of Cygnus, located roughly 1,300 light years away from Earth. It is visible to the naked eye as a blue-white hued star with a combined apparent visual magnitude of 4.74.
The primary component and brightest member of this system, designated 59 Cyg Aa, is a rapidly rotating Be star with a stellar classification of B1.5 Vnne. This is a well-studied star thanks to pronounced spectral variations that have been observed since 1916, and two short-term shell star phases that were observed in 1973 and 1974–5. It is actually a confirmed spectroscopic binary system with a high temperature subdwarf O-type companion in a 28-day orbital period. The latter is heating the nearest side of the circumstellar gaseous disk that surrounds the primary.
Orbiting the primary pair is 59 Cyg Ab, a magnitude 7.64 A-type main-sequence star of class A3V, located at an angular separation of . A fourth component is a magnitude 9.8 A-type giant star of class A8III at a separation of along a position angle (PA) of 352°, as of 2008. The fifth companion is magnitude 11.7 at a separation of and a PA of 141°. Gaia Data Release 2 suggests that the companions at and are respectively and away and moving in approximately the same direction as the primary triple.


NGC 637

NGC 637 is an open cluster of stars in the northern constellation of Cassiopeia, positioned about 1.5° to the WNW of the star Epsilon Cassiopeiae. The cluster was discovered on 9 November 1787 by German-born English astronomer William Herschel. It is located in the Perseus Arm of the Milky Way, at a distance of approximately from the Sun. The cluster is small but compact, and is readily visible in a small telescope.
This is a young cluster with an estimated age of 5–15 million years. It has a trumpler class of I2m, indicating it is strongly concentrated (I) with an intermediate range of brightness variation (2) and a moderate richness of stars (m). The cluster has 55 members and an angular radius of 4′.2, corresponding to a physical radius of . It has a core radius of .
The seven brightest members are all over 10th magnitude, with five known to be variable. A total of four β Cephei-type variables have been identified, one of the highest such totals for an open cluster. A classical Be star candidate has been detected. The distribution of the cluster's stars on the Hertzsprung–Russell diagram shows a noticeable gap on the main sequence, which is not explained by missing data.


33 Arietis

33 Arietis (abbreviated 33 Ari) is a binary star in the northern constellation of Aries. "33 Arietis" is the Flamsteed designation. The combined apparent magnitude of 5.33 is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 14.09 mas, the distance to this system is approximately .
The primary component is an A-type main sequence star with a magnitude of 5.40 and a stellar classification of A3 V. It has a magnitude 8.40 companion at an angular separation of 28.6 arcseconds. An excess of infrared emission suggests the presence of circumstellar dust in this system. In the 24μm band, this debris disk has a mean temperature of 815 K, which puts it at a radius of 0.85 astronomical units (AU) from the primary star. Excess emission appears in the 70μm band, which has a temperature of 103 K and a radius out to 42 AU.


Sigma Serpentis

Sigma Serpentis, Latinized from σ Serpentis, is a star in the equatorial constellation Serpens. It is faintly visible to the naked eye with an apparent visual magnitude of +4.82. Based upon an annual parallax shift of 36.67 mas as seen from Earth, it is located 89 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −49 km/s.
Barry (1970) assigned this star a stellar classification of F3 V, indicating an ordinary F-type main-sequence star. However, Houk and Swift (1999) classified it as A9 Ib/II, suggesting instead that this is an evolved F-type bright giant/supergiant. It is about one billion years old and is spinning with a projected rotational velocity of 77.7 km/s. The star has an estimated 1.58 times the mass of the Sun and is radiating 7.7 times the Sun's luminosity from its photosphere at an effective temperature of 6,952 K.


HD 98649

HD 98649 is a G-type yellow dwarf star, classified as a G4V, that has the same mass and diameter as the Sun, but has only 86% of its luminosity. HD 98649 is about 138 light years from earth. HD 98649 is found in the Crater constellation.
Planetary system.
From 1998 to 2012, the star was under observance from "the CORALIE echelle spectrograph at La Silla Observatory".
In 2012, a long-period, wide-orbiting planet was deduced by radial velocity. This was published in November.
The discoverers noted, "HD 98649b is in the top five of the most eccentric planetary orbit and the most eccentric planet known with a period larger than 600 days." The reason for this eccentricity is unknown. They also submit it as a "candidate for direct imaging", once it gets out to "10.4 AU at apoastron" and 250 milliarcseconds of separation relative to Earth.

Sun comparison.
Chart compares the Sun to HD 98649.


NGC 407

NGC 407 is an edge-on spiral or lenticular galaxy located in the constellation Pisces. It was discovered on September 12, 1784 by William Herschel. It was described by Dreyer as "very faint, very small, southwestern of 2.", the other being NGC 410.


55 Cygni

55 Cygni (55 Cyg) is a blue supergiant star in the constellation Cygnus. It is thought to be a member of the Cygnus OB7 stellar association at about 2,700 light years.
Its apparent magnitude is 4.86, but this is slightly variable and the star is also called V1661 Cyg. When first analysed, it was classified as an irregular supergiant variable, but subsequent studies have treated it as an Alpha Cygni variable. It shows pulsations with multiple periods from a few hours to 22 days, and both p- and g-modes. Apart from p- and g-modes, strange mode and associated instabilities have also been found in models of this star. The spectrum also shows variation, leading to different classifications being given for the star.
The exact properties of 55 Cygni are not known precisely and are also variable. It is a hot luminous supergiant several hundred thousand times as luminous as the sun. This star was originally a standard for the B3 Ia spectral type.
The type of pulsations that 55 Cyg exhibits suggest that it was previously a red supergiant that has shed its outer layers. The most massive red supergiants are expected to pass through a blue supergiant phase before becoming a Wolf-Rayet star and eventually exploding as a type Ib or Ic supernova.


Alruba

Alruba, a name derived from Arabic for "the foal", is a suspected astrometric binary star system in the northern circumpolar constellation of Draco. It is just barely visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.76. Based on parallax measurements obtained during the Gaia mission, it is located at a distance of about from the Sun. The system is drifting closer with a radial velocity of −2 km/s.
The visible component is an A-type main-sequence star with a stellar classification of A0 V. It is about 58 million years old with three times the mass of the Sun and has a high rate of spin, showing a projected rotational velocity of 170 km/s. The star is radiating 147 times the luminosity of the Sun from its photosphere at an effective temperature of 9,226 K. The system is a source for X-ray emission, which is most likely coming from the unseen companion.
Nomenclature.
In the "Henry Draper catalogue" this system has the designation HD 161693, while it has the identifier HR 6618 in the "Bright Star Catalogue".
It bore the traditional Arabic name الربع "Al Rubaʽ" "the foal" (specifically a young camel born in the spring), a member of the Mother Camels asterism in early Arabic astronomy.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name "Alruba" for this star on 1 June 2018 and it is now so entered on the List of IAU-approved Star Names.


Kepler-345b

Kepler-345b is an Exoplanet, orbiting around the star Kepler-345. It was discovered in 2014, by the Kepler space probe.


NGC 604

NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is among the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million light-years, its longest diameter is roughly 1,520 light years (~460 parsecs) (14.38031 exameters), over 40 times the size of the visible portion of the Orion Nebula. It is over 6,300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Its gas is ionized by a cluster of massive stars at its center with 200 stars of spectral type O and WR, a mass of 105 solar masses, and an age of 3.5 million years; however, unlike the Large Magellanic Cloud's Tarantula Nebula central cluster (R136), NGC 604's one is much less compact and more similar to a large stellar association.


NGC 6204

NGC 6204 is an open cluster in the constellation Ara, lying close to the galactic equator. It is 3,540 ly (1,085 pc) distant from Earth. The cluster was discovered on 13 May 1826 by British astronomer James Dunlop.


NR Canis Majoris

NR Canis Majoris is a binary star system in the southern constellation of Canis Major, located to the east of Sirius and Gamma Canis Majoris near the constellation border with Puppis. It has a yellow-white hue and is dimly visible to the naked eye with a combined apparent visual magnitude that fluctuates around 5.60. It is located at a distance of approximately 297 light years from the Sun based on parallax. The system is drifting closer to the Sun with a radial velocity of −29 km/s, and in about three million years it is predicted to approach within . At that time, the star will become the brightest in the night sky, potentially reaching magnitude −0.88.
The magnitude 5.66 primary component is an F-type main-sequence star with a stellar classification of F2V. It is a Delta Scuti variable that varies by a few hundredths of a magnitude over roughly 16 hours. The star is an estimated 1.5 billion years old. It has a high rate of spin with a projected rotational velocity of 185 km/s, which is giving the star an equatorial bulge that is estimated to be 8% larger than the polar radius.
The secondary companion is magnitude 9.23 and lies at an angular separation of along a position angle of 39°, as of 2005.


HD 83443

HD 83443 is an orange dwarf star approximately 134 light-years away in the constellation of Vela. As of 2000, at least one extrasolar planet has been confirmed to be orbiting the star.
The star HD 83443 is named Kalausi. The name was selected in the NameExoWorlds campaign by Kenya, during the 100th anniversary of the IAU. The word Kalausi means a very strong whirling column of wind in the Dholuo language.
Planetary system.
The planet HD 83443 b was discovered in 2000 by the Geneva Extrasolar Planet Search Team led by Michel Mayor. It has a minimum mass comparable to Saturn's, and its orbit at the time of discovery was one of the shortest known taking only three days to complete one revolution around the star. This hot Jupiter is likely to be slightly larger than Jupiter in radius.
In 2000, the same year that planet b was found, another planet around HD 83443 was announced by the Geneva Team. The new planet was designated as "HD 83443 c". It had a mass smaller than planet b and a short, very eccentric orbit. Its orbital period, 28.9 days, was especially interesting, because it indicated a 10:1 orbital resonance between the planets. However, a team led by astronomer Paul Butler did not detect any signal indicating the existence of the second planet. New observations by the Geneva team could not detect the signal either and the discovery claim had to be retracted. The origin of the signal, which was "highly significant" in the earlier data is not yet clear.


Theta Eridani

Theta Eridani (θ Eridani, abbreviated Theta Eri, θ Eri) is a binary system in the constellation of Eridanus. Its two components are designated θ¹ Eridani, formally named Acamar (the traditional name of the system), and θ² Eridani. The system's distance from the Sun as measured by the Hipparcos astrometry satellite is approximately 120 light-years.
Nomenclature.
"Theta Eridani" is the system's Bayer designation; "θ¹" and "θ² Eridani" those of its two components.
The system bore the traditional name "Acamar", derived from the Arabic آخِر النَّهْر "Ākhir an-nahr" which means "the end of the river", via a Roman-alphabet handwriting misread "rn" to "m". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Acamar" for "θ¹ Eridani" on 20 July 2016 and it is now so entered in the IAU Catalog of Star Names.
The term "Ākhir an-nahr" or "Achr al Nahr" appeared in the catalogue of stars in the "Calendarium of Al Achsasi Al Mouakket", which was translated into Latin as "Postrema Fluminis".
Historically, Acamar represented the end of the constellation Eridanus. Now that distinction is held by the star Achernar, which shares the same Arabic etymology. Achernar is not visible from the Greek isles (latitudes > 33° North), hence the choice of Acamar as the river's end during the time of Hipparchus and later Ptolemy.
In Chinese, (), meaning "Celestial Orchard", refers to an asterism consisting of Theta Eridani, Chi Eridani, Phi Eridani, Kappa Eridani, HD 16754, HD 23319, HD 24072, HD 24160, Upsilon4 Eridani, Upsilon3 Eridani, Upsilon2 Eridani and Upsilon1 Eridani. Consequently, the Chinese name for Theta Eridani itself is (, .)
Stellar system.
Theta Eridani is a binary system with some evidence suggesting it is part of a multiple star system. The main star, θ¹ Eridani, is of spectral class A4 with a +3.2 apparent magnitude. Its companion star, θ² Eridani, is of spectral class A1 with an apparent magnitude of +4.3. The angular separation of the two stars is equal to 8.3 arcseconds.
Ptolemy described Theta Eridani as a first-magnitude star, which some have taken to be in fact Achernar, which today appears just above the horizon in Alexandria where Ptolemy lived. Achernar, however, was not visible to Ptolemy (it is from Alexandria today due to precession); its declination in 100CE was -67, making it invisible even at Aswan. Ptolemy's Eridanus thus without doubt ended at Theta Eridani, which rose about 10 degrees above the horizon from Alexandria. This fact besides positively identifying Theta Eridani as the original "end of the river", also strengthens the case for it having been first magnitude in ancient times.
External links.
Jim Kaler's Stars: Acamar


TY Coronae Australis

TY Coronae Australis (abbreviated as TY CrA), is a young star system around 3 million years old in the constellation Corona Australis. It is composed of a blue-white B-class star around triple the Sun's mass and a cooler smaller companion around half its mass (or 1.6 times that of the Sun). The system is an eclipsing binary with a period of 2.8 days.


Alpha Comae Berenices

Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices (Berenice's Hair), away. It consists of two main sequence stars, each a little hotter and more luminous than the Sun.
Alpha Comae Berenices is said to represent the crown worn by Queen Berenice. The two components are designated Alpha Comae Berenices A (officially named Diadem , the traditional name for the system) and B.
Nomenclature.
"α Comae Berenices" (Latinised to "Alpha Comae Berenices") is the system's Bayer designation. The designations of the two components as "Alpha Comae Berenices A" and "B" derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
The system bore the traditional names "Diadem" and "Al Dafirah," the latter derived from the Arabic الضفيرة "ađ̧-đ̧afīrah" "the braid". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Diadem" for the component Alpha Comae Berenices A on 1 February 2017 and it is now so included in the List of IAU-approved Star Names.
In Chinese, (), meaning "Left Wall of Supreme Palace Enclosure", refers to an asterism consisting of Alpha Comae Berenices, Eta Virginis, Gamma Virginis, Delta Virginis and Epsilon Virginis. Consequently, the Chinese name for Alpha Comae Berenices itself is (, .), representing (), meaning "The First Eastern General". 東上將 (Dōngshǎngjiāng), westernized into "Shang Tseang", but that name was designated for "v Comae Berenices" by R.H. Allen and the meaning is "a Higher General".
Properties.
Although Alpha Comae Berenices bears the title "alpha", at magnitude 4.32 it is actually fainter than Beta Comae Berenices.
It is a binary star, with almost equal components of magnitudes 5.05 m and 5.08 m orbiting each other with a period of 25.87 years. The system, estimated to be 58 light-years distant, appears so nearly "edge-on" from the Earth that the two stars appear to move back-and-forth in a straight line with a maximum separation of only 0.7 arcsec. Eclipses are predicted to occur between the two components however they have not been successfully observed due to miscalculations of the time of eclipse.
The mean separation between them is approximately 10 AU, about the distance between the Sun and Saturn.
The binary star has a visual companion, CCDM J13100+1732C, of apparent magnitude 10.2, located 89 arcseconds away along a position angle of 345°.
Alpha Comae Berenicis forms an isosceles triangle with globular star clusters Messier 53 and NGC 5053. The apparent diameter of this triangle is a little more than one degree. The location of Alpha Comae Berenicis is westward (preceding) of both globular star clusters.


HD 222582

HD 222582 is a multiple star system in the equatorial constellation of Aquarius. It is invisible to the naked eye with an apparent visual magnitude of 7.7, but can be viewed with binoculars or a small telescope. The system is located at a distance of 138 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +12 km/s. It is located close enough to the ecliptic that it is subject to lunar occultations.
The primary member of this system, designated component A, is an ordinary G-type main-sequence star with a stellar classification of G5V. The physical properties of the star are similar enough to the Sun that it is considered a candidate solar twin. It is about 6.5 billion years old with an inactive chromosphere and is spinning with a low projected rotational velocity of 1.7 km/s. The mass and metallicity of this star are essentially the same as the Sun. It has a 14% larger radius and is radiating 1.3 times the luminosity of the Sun from its photosphere at an effective temperature of 5,790 K.
Component B of this system is a close binary system with the components designated HD 222582 Ba and Bb. The pair have a combined class of M4.5 V+ and about 20% the mass of the Sun.
Planetary system.
In November 1999, a dense superjovian planet was announced orbiting the primary by the California and Carnegie Planet Search. Designated component 'b', it was discovered using the radial velocity method, using 24 observations over a period of 1.5 years. The exoplanet is orbiting with a period of and a very large eccentricity of 0.76, ranging in distance from out to away from the primary.


NGC 803

NGC 803 is a spiral galaxy located in the constellation Aries about 70 million light-years from the Milky Way. It was discovered by the German–British astronomer William Herschel in 1784.


HD 20868

HD 20868 is a star in the southern constellation Fornax. With an apparent visual magnitude of 9.92, it is much too dim to be visible to the naked eye. Parallax measurements give a distance estimate of 156 light years from the Sun. It is drifting further away with a radial velocity of +46.2 km/s, having come to within about around 312,000 years ago.
This object is a K-type star with a stellar classification of K3/4 III/V. It is around eight billion years old with 76% of the mass of the Sun and 73% of the Sun's radius. It is radiating 25.5% of the luminosity of the Sun from its photosphere at an effective temperature of 4,811 K. The metallicity of the star is near solar, meaning it has about the same abundance of iron as in the Sun.
The star HD 20868 is named Intan. The name was selected in the NameExoWorlds campaign by Malaysia, during the 100th anniversary of the IAU. Intan means diamond in the Malay language.
Planetary system.
In October 2008 a planet, HD 20868 b, was discovered. This object was detected using the radial velocity method by search programs conducted using the HARPS spectrograph. The orbital solution indicates this is a giant planet in a highly elliptical orbit around the host star.


QS Telescopii

QS Telescopii is a faint binary star system in the constellation Telescopium. It is composed of a white dwarf and main sequence donor star, in this case the two are so close and fused into orbit facing one another. Known as polars, material from the donor star does not form an accretion disk around the white dwarf, but rather streams directly onto it. This is due to the presence of the white dwarf's strong magnetic field.


WZ Cephei

WZ Cephei is an eclipsing binary star of W Ursae Majoris-type in the constellation of Cepheus, located 880 light years away from the Sun. The stars orbit around a common orbital barycenter every 0.41744 days (slightly over 10 hours). Timing analyses have revealed the possible presence of a third low-mass stellar companion in a wide orbit.
Presence of a third body.
According to Zhu & Qian (2009) a third low-mass object of stellar nature could be responsible of orbital period variations observed for WZ Cep with a periodicity of roughly 32 years. Such a companion would yield a minimum mass of 0.17 Solar masses and be located 26.6 Astronomical Units (nearly the same orbital separation of Neptune in Solar System) from the eclipsing binary. The star could likely turn out a Proxima Centauri-analog, with inferred luminosity 3.7 percent that of Sun and 20 percent of its radius, according to mass-radius relationship.


NGC 2906

NGC 2906 is a spiral galaxy located in the constellation Leo. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 2906 is about 75,000 light years across. It was discovered by William Herschel on December 28, 1785.
The galaxy is characterised by a normal star formation rate, which has been calculated to be 0.8 per year. The total mass of the galaxy is estimated to be . A total of 241 HII regions have been identified in the galaxy.
One supernova has been observed in NGC 2906, SN 2005ip. The supernova was discovered by T. Boles on November 6, 2005, with a 0.35m refractor, with an estimated apparent magnitude 15.5 and was identified as a type II supernova, probably within a few weeks past explosion. As the supernova declined in brightness, it reached a plateau that lasted for a bit more than two years and its spectrum became dominated by narrow lines (IIn), an unusual feature of supernovae, that was attributed to the interaction of the supernova with dust located around it. It is also possible that the supernova created dust.
NGC 2906 is member of a group of galaxies, the NGC 2894 group. Other galaxies identified as members of the cluster are NGC 2882, NGC 2894, and IC 450.


Laevens 3

Laevens 3 is a globular cluster in the constellation of Delphinus. It belongs to the Milky Way but orbits far from the centre. The cluster is named after Benjamin P. M. Laevens, the discoverer. It was first observed in 2015 using Pan-STARRS 1.
It is located 210,000 light years from Earth in the outer galactic halo. Its orbit takes it to 133,000 ly from galactic centre and out to 279,000 ly. The half light diameter is only 37 light years. The metallicity is −1.8 dex. The cluster is about 13 billion years old. The brightness is equivalent to 1,125 Suns.


Zeta Pictoris

ζ Pictoris, Latinised as Zeta Pictoris, is a solitary star in the southern constellation of Pictor. It is visible to the naked eye with an apparent visual magnitude of +5.43. Based upon an annual parallax shift of 28.00 mas as seen from the Earth, the system is located 116.5 light years from the Sun.
This is an evolving F-type subgiant star with a stellar classification of F6 IV. It is a thin disk star with an estimated 1.4 times the mass of the Sun and about 5.3 times the Sun's radius. At the age of 2.6 billion years, Zeta Pictoris is spinning with a projected rotational velocity of 5.6 km/s.


List of stars in Ursa Major

This is the list of notable stars in the constellation Ursa Major, sorted by decreasing brightness.


HD 220773

HD 220773 is a 7th-magnitude star approximately 165 light years away in the constellation of Pegasus.
The survey in 2015 have ruled out the existence of any additional stellar companions at projected distances from 31 to 337 astronomical units.
Planetary system.
The star is orbited by an exoplanet discovered in 2012. It is around 1.45 times the mass of Jupiter, orbiting very eccentric orbit with semimajor axis of around 5 AU and taking 10.2 years to complete an orbit. If additional inner terrestrial planets do exist in HD 220773 system, these must have eccentric orbits for planetary system to remain stable.


Alpha Cancri

Alpha Cancri (α Cancri, abbreviated Alpha Cnc, α Cnc), also named Acubens , is a star system in the constellation of Cancer.
Nomenclature.
"α Cancri" (Latinised to "Alpha Cancri") is the star's Bayer designation.
The traditional name "Acubens" (Açubens) is derived from the Arabic , "the claws" A second name, Sertan , derives from the Arabic "al-saraṭān" 'the crab'. The International Astronomical Union Working Group on Star Names (WGSN) choose 'Acubens' as the proper name for this star.
Properties.
Alpha Cancri is a fourth-magnitude star with an apparent magnitude of 4.20, making it barely visible to the naked eye under good lighting conditions. Nevertheless, it is 23 times more luminous than the Sun. Its stellar classification is A5m. The distance of Alpha Cancri calculated from the Gaia Data Release 2 parallax is roughly 50 parsecs from Earth, or approximately 164 light years away.
Since it is near the ecliptic, it can be occulted by the Moon and very rarely by planets.
Star system.
The primary component, α Cancri A, is a white A-type main sequence dwarf with an apparent magnitude of +4.26. Its companion, α Cancri B, is an eleventh magnitude star. In the year 1836, its position angle was observed at 325 degrees with a separation from the main star α Cancri A of 11.3arcseconds.
From studying its light curve during occultation, it is thought that α Cancri A may itself be a close binary, consisting of two stars with similar brightness and a separation of 0.1arcseconds.
In modern culture.
USS "Acubens" (AKS-5) was a United States navy ship.


62 Aquilae

62 Aquilae is a single star located about 427 light years away from the Sun in the equatorial constellation of Aquila. "62 Aquilae" is its Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.67.
This is an aging giant star with a stellar classification of K4 III, having exhausted the supply of hydrogen at its core and expanded to 23 times the girth of the Sun. It is 11.2 billion years old with 0.89 times the Sun's mass. The star is radiating 153 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,246 K.


GX 339-4

GX 339-4 is a moderately strong variable galactic low-mass X-ray binary (LMXB) source and black-hole candidate that flares from time to time. From spectroscopic measurements, the mass of the black-hole was found to be at least of 5.8 solar masses.
During the outbursts GX 339-4 shows evolution of quasi-periodic oscillations (QPOs). In the rising phase the QPO frequency monotonically increase as the CENBOL propagates closer to the black hole and in the declining phase the QPO frequency monotonically decreases since the CENBOL recedes away from the black hole after viscosity is decreased. The frequency variation is thus well modeled by the propagating and oscillating shock in the sub-Keplerian flow. The entire spectrum also fits very well using two component advective flow solution.
A strong, variable relativistic jet, emitting from radio to infrared wavelengths was observed by several studies.


59 Serpentis

59 Serpentis, also known as d Serpentis, is a multiple star in the constellation Serpens. It is a triple star system. The primary system is a spectroscopic binary consisting of an A-type star and an orange giant, while the secondary is another orange giant. The system shows irregular variations in brightness between magnitudes 5.17 and 5.2.


Eta Coronae Australis

The Bayer designation η Coronae Australis (Eta Coronae Australis) is shared by two stars, in the constellation Corona Australis:


NGC 7043

NGC 7043 Is a barred spiral galaxy located about 200 million light-years away in the constellation of Pegasus. NGC 7043 is part of a pair of galaxies that contains the galaxy NGC 7042. It has an estimated diameter of 73,100 light-years. NGC 7043 was discovered by astronomer Albert Marth on August 18, 1863.


M59-UCD3

M59-UCD3 is an ultra-compact dwarf galaxy located near the Messier 59 galaxy. , it is the second-densest galaxy currently observed, second to M85-HCC1.


Machina Electrica

Machina Electrica (Latin for "electricity generator") was a constellation created by Johann Bode in 1800. He created it from faint stars between Fornax and Sculptor, to the south of Cetus. It represented an electrostatic generator. The constellation was somewhat popular during the 19th century and had appeared in a number of star charts, but was eventually rendered obsolete when the International Astronomical Union standardized constellation boundaries in 1930 and is now no longer in use.


U Hydrae

U Hydrae is a single star in the equatorial constellation of Hydra, near the northern constellation border with Sextans. It is a semiregular variable star of sub-type SRb, with its brightness ranging from visual magnitude (V) 4.7 to 5.2 over a 450-day period, with some irregularity. This object is located at a distance of approximately 680 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −26 km/s.
This is a carbon-rich red giant star on the asymptotic giant branch – a carbon star – with s-process elements appearing in the spectrum. It has a stellar classification of with a carbon star class of . The star is losing mass at the rate of ·yr−1, with an outflow velocity of . Technetium has been detected in the spectrum, suggesting the star has experienced a third dredge-up episode due to thermal pulses of the helium-burning shell some time within the last 100,000 years.
An ultraviolet (UV) excess has been detected coming from an extended elliptical ring that surrounds this star. It has a mean angular radius of and lines up with a detached shell of dusty material that was previously detected in the infrared band. The material was most likely ejected from the star due to mass loss episodes. The probable cause of the UV emission is from the movement of the star through space and possibly shock-excited molecules of H2. The emission does not show a bow-shock-like structure.


S Vulpeculae

S Vulpeculae is a star located in the constellation Vulpecula. A supergiant star, it is around 382 times the diameter of the Sun.
S Vulpeculae was first suspected of varying in brightness in 1836 and this was confirmed by 1862. A pulsating variable that grows and shrinks as it changes in brightness, it has been variously classified as an RV Tauri variable, a semiregular variable star, or a Cepheid variable.
S Vulpeculae is now confirmed as a classical Cepheid variable with one of the longest known periods at 68 days, although the period has changed several times. As such, it is also one of the cooler and more luminous of the Cepheids, and it lies close to the zone where semiregular variable stars are found. The shape and amplitude of the light curve varies significantly from cycle to cycle and secularly. The apparent magnitude ranges from 8.69 to 9.42. The spectrum varies from early G to late K as it pulsates, with TiO bands typical of an M1 star when the star is coolest.


NGC 2992

NGC 2992 is a Seyfert galaxy located in the constellation Hydra. It was discovered in 1785 by William Herschel. It has a close companion, NGC 2993.


Iota Leonis

Iota Leonis, Latinized from ι Leonis, is a triple star system in the constellation Leo. The system is fairly close to the Sun, at only 79 light-years (24.2 parsecs) away, based on its parallax. The system has a combined apparent magnitude of 4.00 making it faintly visible to the naked eye. It is moving closer to the Sun with a radial velocity of −10 km/s.
Iota Leonis has a spectral type of F3 IV, matching that of an F-type subgiant star. It is a spectroscopic binary, which means it is a binary star with components that are too close together to be able to resolve individually through a telescope. In this case, light from only the primary star can be detected, and it is considered single-lined.
The third component in the star system is designated Iota Leonis B. It orbits the central pair almost every 200 years, and with its perihelion passage in 1948, the separation between the two is steadily growing. Iota Leonis B has a mass approximately 8% greater than that of the Sun. It is a G-type main-sequence star, like the Sun.
Name.
In Chinese, (), meaning "Right Wall of Supreme Palace Enclosure", refers to an asterism consisting of ι Leonis, β Virginis, σ Leonis, θ Leonis and δ Leonis. Consequently, the Chinese name for ι Leonis itself is (, .), representing (), meaning "The Second Western General". 西次將 (Xīcìjiāng), spelled Tsze Tseang by R.H. Allen, means "the Second General"


Tau Librae

Tau Librae, Latinized from τ Librae, is the Bayer designation for a binary star system at the southern edge of the zodiac constellation of Libra. It can be seen with the naked eye, having an apparent visual magnitude of 3.68. The distance to this system is around 367 light years, as determined from an annual parallax shift of 8.89 mas.
Judging by its motion through space and physical properties, this system is a member of the Upper Centaurus Lupus group of the Scorpius-Centaurus Association. It is double-lined spectroscopic binary with an orbital period of just 3.3 days and an eccentricity of 0.28. The primary, component A, is a B-type main sequence star with a stellar classification of B2.5 V. It is estimated to hold more than seven times the mass of the Sun and have over three times the Sun's radius. It is only 31.5 million years old and is spinning relatively rapidly with a projected rotational velocity of 134 km/s.
The system is emitting an infrared excess, suggesting the presence of a circumstellar disk of material.


Kappa Pegasi

Kappa Pegasi (κ Peg, κ Pegasi) is a triple star system in the constellation Pegasus. It has an apparent brightness of +4.13 magnitude and belongs to the spectral class F5IV; a subgiant star. No proper name is associated to this star.
This system consists of two components, designated Kappa Pegasi A and B, that are separated by an angular distance of 0.235 arcseconds. The binary nature of this pair was discovered by Sherburne W. Burnham in 1880. They orbit around each other every 11.6 years with a semimajor axis of 0.4 arcseconds. The brighter member of the pair, Kappa Pegasi B, is actually a spectroscopic binary, with the components designated Kappa Pegasi Ba and Kappa Pegasi Bb. They orbit about each other every six days. There is a fourth component, Kappa Pegasi C, which may be an optical companion.


Nu Serpentis

ν Serpentis, Latinized as Nu Serpentis, is a solitary star in the Serpens Cauda section of the equatorial constellation of Serpens. It is a white-hued star that is faintly visible to the naked eye with an apparent visual magnitude of 4.32. Based upon an annual parallax shift of 16.05 mas as seen from the Sun, it is about 203 light years from the Sun. The star is drifting further away with a radial velocity of +5 km/s.
This is an A-type main-sequence star with a stellar classification of A2V, and is generating energy through hydrogen fusion at its core. It is 350 million years old with a high rate of spin, showing a projected rotational velocity of 123 km/s. The star has 2.64 times the mass of the Sun and 3.0 times the Sun's radius. It is radiating 76 times the Sun's luminosity from its photosphere at an effective temperature of 9,120 K. Nu Serpentis has an optical companion, a magnitude +9.4 star at an angular separation of 46 arcseconds.


UX Antliae

UX Antliae is post-AGB star. It is an R Coronae Borealis variable star that has a base apparent magnitude of around 11.85, with irregular dimmings down to below magnitude 18.0.
Researchers David Kilkenny and J.E. Westerhuys of the South African Astronomical Observatory confirmed that UX Antliae was an R Coronae Borealis variable in 1990 after noting the similarity of its spectrum to the RCB star W Mensae. It had been suspected of being one since 1940, but had been little-studied and exhibited no characteristic declines between 1975 and 1990.
Assuming that its absolute magnitude is around -5, it has been estimated as lying 25000 parsecs distant from Earth. Kilkenny and Westerhuys noted that its spectrum fit with that of a star of spectral class F, although was deficient in hydrogen. It has around 70% the mass of the Sun and an effective (surface) temperature of around 7000 K.
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HD 50499

HD 50499 is a star in the constellation of constellation of Puppis. With an apparent visual magnitude of 7.21, this star is too faint to be in naked eye visibility. It is located at a distance of 151 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +36.7 km/s.
This object is a G-type main-sequence star with a stellar classification of G0/2 V. It is positioned 0.6 magnitudes above the main sequence, which may be explained by a high metallicity and an older age. Vogt et al. (2005) estimated its age as about 6.2 billion years, although more recent estimates give a younger age of around 2.4 billion years. The star has 1.31 times the mass of the Sun and 1.42 times the Sun's radius. It is radiating 2.38 times the luminosity of the Sun from its photosphere at an effective temperature of 6,099 K. As of 2005, at least one extrasolar planet has been confirmed to be orbiting the star.
Planetary system.
The first planet discovered, HD 50499 b, is a gas giant with mass of 1.7 times Jupiter. It is a long period, taking 351 weeks to orbit the star. The planet's eccentric orbit passes through the average distance of 574 Gm or 18.6 μpc.
The planet was discovered by four team members including Steven Vogt in 2005 using their radial velocity method, which used to measure changes in red- and blue-shifting of the star that indicate the presence of planets caused by gravitational tug. There is also a linear trend in the radial velocities, which may indicate an additional outer planet. The best two-planet model gives a different period and mass for the inner planet (9.8 years and 3.4 Jupiter masses), with an outer planet of 2.1 Jupiter masses in a 37-year orbit. However the two-planet model does not represent a significant improvement over the model with one planet and a linear trend, so more observations are needed to constrain the parameters of the outer planet.
Rickman et al. (2019) gave updated models of the planets and their orbits, shown below. The "HD 50499c" is listed as confirmed planet as in 2020.


Lambda Ursae Minoris

Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38 and is approximately 880 light years from Earth.
Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core. AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes. Its variability was discovered from Hipparcos astrometry and it was entered into the General Catalogue of Variable Stars in 1999.


PZ Cassiopeiae

PZ Cassiopeiae is a red supergiant star located in the Cassiopeia constellation, and a semi-regular variable star.
Characteristics.
PZ Cassiopeiae is a luminous red supergiant star, one of the largest stars currently known with a radius over 1,000 times the Sun's radius (), and also one of most luminous of its type, around 200,000 times more luminous than the Sun (). It is likely to be part of the Cas OB5 stellar association although apparently much younger than the other stars in the association. The star is losing mass at around and has also once been described as a hypergiant.
Its distance from Earth was initially estimated to be around 7,800 light-years (2.4 kiloparsecs). Subsequent studies of the star using the water masers that surround it have allowed to refine both the distance and the parameters of this star, deriving an accurate parallax of , corresponding to a distance of 9,160 light-years (2.81 kiloparsecs), that translates a luminosity for it around , and an initial mass of 20 to 25 times that of the Sun. These parameters are all similar to those estimated for the red hypergiant VY Canis Majoris.
A less reliable Gaia Data Release 2 parallax of gives the star a luminosity below with a corresponding radius of .
PZ Cas is a slow semi-regular variable star with the period quoted as 925 days in the General Catalogue of Variable Stars, although periods of 850 and 3,195 days have been derived. The visual range is approximate magnitude 8-10, large for this type of variable.
Supergiant or AGB star.
PZ Cas has traditionally been treated as a massive supergiant, comparable to others such as VY CMa, but there is some evidence that it is a possible less massive O-rich S- or SC-type Asymptotic Giant Branch (AGB) or post-AGB star. It shows enrichment of Zr and Ba, but not Li as would be expected for a true supergiant.
Companion.
PZ Cas has a Cepheid variable companion, a 13th magnitude star 12" away.


Delta Sagittae

Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main-sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax.
Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected. It has an orbital period of about 10 years and an eccentricity of about 0.44. It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way.
Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy.
Naming.
In Chinese, (), meaning "Left Flag", refers to an asterism consisting of δ Sagittae, α Sagittae, β Sagittae, ζ Sagittae, γ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name for δ Sagittae itself is (, .)


Psi Ophiuchi

Psi Ophiuchi, which is Latinized from ψ Ophiuchi, is a single star in the equatorial constellation of Ophiuchus, located next to the western constellation border with Scorpius. It has an orange hue and is visible to the naked eye as a faint point of light with an apparent visual magnitude of 4.50. The distance to this object is approximately 199 light years based on parallax.
This is an aging giant or bright giant star with a stellar classification of K0- II-III, which indicates it has exhausted the supply of hydrogen at its core then cooled and expanded. At present it has 11 times the girth of the Sun, while having 1.6 times the Sun's mass. It is a red clump giant, meaning it is on the horizontal branch and is generating energy through core helium fusion. The star is radiating 66 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,864 K.


Epsilon Telescopii

Epsilon Telescopii, Latinized from ε Telescopii, is a solitary, orange-hued star in the southern constellation of Telescopium. It is visible to the naked eye with an apparent visual magnitude of +4.53. Based upon an annual parallax shift of 7.80 mas as seen from Earth, it is located roughly 420 light years from the Sun, give or take 30 light years.
This an evolved K-type giant with a stellar classification of K0 III. It displays an infrared excess, suggesting the presence of an orbiting disk of dust. The star is radiating 293 times the Sun's luminosity from its photosphere at an effective temperature of 4,996 K. It has a 13th magnitude optical companion at an angular separation of 16.30 arcseconds along a position angle of 233°, as of 2000.


70 Aquilae

70 Aquilae, abbreviated 70 Aql, is a single orange-hued star in the equatorial constellation of Aquila. "70 Aquilae" is its Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.90. The distance to 70 Aquilae, as determined from its annual parallax shift of , is around 940 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −9 km/s.
Classification.
Perkins et al. (1989) found a stellar classification of for this star, suggesting it is a K-type giant with abundance anomaly of barium. Houk and Swift (1999) matched an ordinary giant with a class of K3 III. Many sources still use the 1991 Bright Star Catalogue classification of K5 II, which instead suggests a bright giant star.
Size and temperature.
The interferometry-measured angular diameter of this star, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of roughly 102 times the radius of the Sun. 70 Aquilae is about 63 million years old with 6 times the mass of the Sun. It is radiating 4,072 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,900 K.
References.
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Gamma Serpentis

Gamma Serpentis (γ Serpentis, γ Ser) is a star in the equatorial constellation Serpens, in the part of the constellation that represents the serpent's head (Serpens Caput). It has an apparent visual magnitude +3.85, which means it is visible to the naked eye. Based upon parallax measurements by the Hipparcos spacecraft, this star is approximately 36.7 light years from Earth.
Properties.
Gamma Serpentis is an ordinary F-type main sequence star with a stellar classification of F6 V. It is larger and more massive than the Sun, with three times the solar luminosity. Based upon its mass, it may have a convection zone in its core region. The projected rotational velocity along the equator is 10.2 km/s. It is younger than the Sun with an estimated age of 3.5 billion years. The effective temperature of the star's outer atmosphere is 6,350 K, giving it the yellow-white-hued glow of an F-type star.
Occasionally Gamma Serpentis is listed as having two 10th magnitude companions, but it appears that these stars are just optical neighbours.
Etymology.
It was a member of indigenous Arabic asterism al-Nasaq al-Sha'āmī, "the Northern Line" of "al-Nasaqān" "the Two Lines", along with β Her (Kornephoros), γ Her (Hejian, Ho Keen) and β Ser (Chow).
According to the catalogue of stars in the "Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars", "al-Nasaq al-Sha'āmī" or Nasak Shamiya were the title for three stars:β Ser as "Nasak Shamiya I", γ Ser as "Nasak Shamiya II", γ Her as "Nasak Shamiya III" (exclude β Her). The star was later given the proper name Ainalhai, from the Arabic عين الحية "‘Ayn al-Ḥayyah" "the Serpent's Eye".
In Chinese, (), meaning "Right Wall of Heavenly Market Enclosure", refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of γ Serpentis, β Herculis, γ Herculis, κ Herculis, β Serpentis, δ Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi. Consequently, the Chinese name for γ Serpentis itself is (, ), represent the state Zheng (鄭) (or Ching), together with 20 Capricorni (according to Ian Ridpath version) in "Twelve States" (asterism).


NGC 4534

NGC 4534 is a spiral galaxy, located in the Canes Venatici constellation. It was discovered on May 1, 1785 by William Herschel, using an 18" reflector telescope.


Eta Piscium

Eta Piscium (η Piscium, abbreviated Eta Psc, η Psc) is a binary star and the brightest point of light in the constellation of Pisces with an apparent visual magnitude of +3.6. Based upon a measured annual parallax shift of 9.33 mas as seen from Earth, it is located roughly 350 light-years distant from the Sun in the thin disk population of the Milky Way.
The two components are designated Eta Piscium A (formally named Alpherg , the traditional name of the system) and B.
Nomenclature.
"η Piscium" (Latinised to "Eta Piscium") is the system's Bayer designation. The designations of the two constituents as "Eta Piscium A" and "B" derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
The system bore the traditional names "Al Pherg" (in this context meaning the emptying) and "Kullat Nunu". At the time that the sun at the March Equinox entered into Pisces having lay in Aries, the system was in the first ecliptic constellation of the Neo-Babylonians, "Kullat Nūnu" − 'Nūnu' being Babylonian for fish and 'Kullat' referring to either the bucket or the cord that binds the fish. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Alpherg" for the component Eta Piscium A on 1 June 2018 (for its official List).
In Chinese, (), meaning "Official in Charge of the Pasturing", refers to an asterism consisting of Eta Piscium, Rho Piscium, Pi Piscium, Omicron Piscium and 104 Piscium. Consequently, the Chinese name for Eta Piscium itself is (, .)
Properties.
At its present distance, the visual magnitude of the system is diminished by an extinction factor of due to interstellar dust.
This system's binary nature was discovered in 1878 by an amateur astronomer, S. W. Burnham. It has an orbital period of roughly 850 years, a semimajor axis of 1.2 arc seconds, and an eccentricity of 0.47.
The primary, component A, is an evolved, magnitude 3.83 G-type giant star with a stellar classification of G7 IIIa. It has a weak magnetic field with a strength of , and is a Gamma Cassiopeiae variable. The companion, component B, is a magnitude 7.51 star.


NGC 5897

NGC 5897 is a globular cluster in the constellation Libra. This satellite of the Milky Way, which is quite remote (located about 41,000 light years away), has a diameter of over 170 light years. With its Shapley–Sawyer Concentration Class of XI, it has very low star density even in its center.
The stars of the cluster have only one per cent of the Sun's metallicity, while the abundance of elements produced by the alpha process is roughly 5 times larger. This means that the cluster formed in a time before the galaxy formed a disk and spiral arms. However, some of the stars are apparently younger, indicating multiple star-forming epochs.
NGC 5897 has a diameter of 12.6 arcminutes and an apparent magnitude of 8.5.


Kepler-25b

Kepler-25b is an extrasolar planet orbiting the star Kepler-25, located in the constellation Lyra. The planet was first detected as a candidate extrasolar planet by the Kepler space telescope in 2011. It was confirmed, in 2012, by Jason Steffen and collaborators using transit-timing variations obtained by the Kepler Space Telescope.


GJ 9827

GJ 9827 is a star in the constellation of Pisces. It is a K-type main-sequence star with an apparent magnitude of 10.250. It is 97 light-years (30 parsecs) away, based on parallax.
The rotation period of the star cannot be determined as in 2020, and can be either around 15 or 30 days, depending on interpretation of available data.
Planetary system.
It has 3 transiting planets seen by the "Kepler" space observatory in their K2 survey. As of October 2017, it is the closest star discovered to have transiting exoplanets found by either the Kepler or K2 missions. The planets (b, c, d) have radii of 1.62, 1.27, and 2.09 times that of the Earth, and periods of 1.209, 3.648, and 6.201 days (ratios 1:3:5). Because of its close distance the system is considered an excellent target for studying atmospherics of exoplanets.
In late 2017, the masses of all three planets were determined using the Planet Finder Spectrograph on the Magellan II Telescope. Planet b was found to be very iron-rich, planet c appears to be mainly rocky, and planet d is a typical volatile-rich planet. GJ 9827b is noted as being one of the densest planets yet found, with its mass containing about ≥50% iron.
More precise radial velocity measurements released in late February 2018 revealed that all three planets have a lower density than Earth and have some amount of volatiles in their compositions. GJ 9827b and c are mainly rocky (containing less than 1% mass fraction of water, and negligible helium and hydrogen) with very thin volatile envelopes, while GJ 9827d is more akin to a Mini-Neptune. The loss of primordial atmosphere was indirectly confirmed in 2020 as no helium was detected at Gliese 9827 d though. With a mass of about 1.5 , GJ 9827c is one of the least massive planets detected with radial velocity. The atmospheres for GJ 9827b and GJ 9827d were not detected at all in 2021 observations.


NGC 264

NGC 264 is a lenticular galaxy located in the constellation Sculptor. It was discovered on August 30, 1834 by John Herschel.


NGC 2022

NGC 2022 is a planetary nebula in the equatorial constellation of Orion, located at a distance of from the Sun. It was first observed by William Herschel on December 28, 1785, who described it as: considerably bright, nearly round, like a star with a large diameter, like an ill-defined planetary nebula. In medium-sized amateur telescopes it looks like small grayish patch of light. It is not very bright but it is still easy to spot it in the eyepiece. The object has the shape of a prolate spheroid with a major to minor axis ratio of 1.2, an apparent size of , and a halo extending out to .
This is a double-shell planetary nebula with a wind-compressed inner shell and a more nebulous second shell. The linear radius of the inner shell is estimated at . It is expanding with a velocity of . The second shell is nearly circular and is expanding more slowly than the inner. The mass of the ionized elements in the planetary nebula is , or 19% of the Sun's mass. A faint outer halo consists of the remains of material ejected during the central star's asymptotic giant branch stage.
NGC 2022 nebula lies 11° away from the Galactic Plane, which position suggests it was formed from a low-mass star. The elemental abundances are similar to those in the Sun, although carbon is about 50% higher and sulfur is a factor of two lower. The central star of this nebula has a visual magnitude of 15.92, a temperature of , and is radiating 852 times the luminosity of the Sun from a photosphere that has only 6.55% of the Sun's radius.


NGC 387

NGC 387 is an elliptical galaxy located in the constellation Pisces. It was discovered on December 10, 1873 by Lawrence Parsons. It was described by Dreyer as "very faint, small, round." Along with galaxies NGC 375, NGC 379, NGC 382, NGC 383, NGC 384, NGC 385, NGC 386 and NGC 388, NGC 387 forms a galaxy cluster called Arp 331.


NGC 354

NGC 354 is a barred spiral galaxy in the constellation Pisces. It was discovered on October 24, 1881 by Édouard Stephan. It was described by Dreyer as "very faint, very small, round, very small (faint) star involved, 14th magnitude star close to west."


NGC 5925

NGC 5925 is an open cluster in the constellation Norma. It is 5070 light-years distant and thought to be around 316 million years old.


K2-32

K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. Four confirmed transiting exoplanets are known to orbit this star. A study of atmospheric escape from the planet K2-32b caused by high-energy stellar irradiation indicates that the star has always been a very slow rotator.
Planetary system.
Discovery.
The star K2-32 was initially found to have three transiting planet candidates by Andrew Vanderburg and collaborators in 2016. The innermost planet candidate, at that time, K2-32b was confirmed using radial velocity measurements made with the Keck telescope. Confirmation of planets c and d was made by Sinukoff "et al." using adaptive optics imaging and computer analysis to eliminate possible false positives.
The Earth-sized planet K2-32e was discovered and validated by René Heller and team in 2019.
Characteristics.
With periods of 4.34, 8.99, 20.66 and 31.71 days the four planets orbits are very close to a 1:2:5:7 orbital resonance chain. The densities of planets b, c, and d are between those of Saturn and Neptune, which suggests large and massive atmospheres. The planet K2-32e with a radius almost identical to that of the Earth is almost certainly a terrestrial planet. All four planets are well inside even the optimistic inner boundary of the habitable zone located at 0.58 astronomical units.


NGC 526

NGC 526 is a pair of interacting lenticular galaxies in the constellation of Sculptor. Both the constituents are classified as S0 lenticular galaxies. This pair was first discovered by John Herschel on September 1, 1834. Dreyer, the compiler of the catalogue described the galaxy as "faint, small, a little extended, the preceding of 2", the other object being NGC 527.


HD 95086

HD 95086 is a pre-main-sequence star. Its surface temperature is 7750 K. HD 95086 is probably similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of −0.25, but is much younger at an age of 17 million years.
Multiplicity surveys did not detect any stellar companions to HD 95086 as of 2013.
Planetary system.
In 2013, one planet, named HD 95086 b, was discovered on a wide orbit by direct imaging. The discovery was confirmed in 2014.
Besides the planet, the star is surrounded by a complex, relatively massive (0.5 ) debris disk, which may consist of up to four belts (Hot, Warm, Cold and Halo) separated by gaps. A small amount (1.4–13)×10−6 of gaseous carbon monoxide was detected in the outer disk, implying a recent collisional cascade followed by cometary activity of fresh debris.


NGC 225

NGC 225 is an open cluster in the constellation Cassiopeia. It is located roughly 2100 light-years from Earth.


Alpha Sextantis

Alpha Sextantis (α Sex, α Sextantis) is the brightest star in the equatorial constellation of Sextans. It is visible to the naked eye on a dark night with an apparent visual magnitude of 4.49. The distance to this star, as determined from parallax measurements, is around 280 light years. This is considered an informal "equator star", as it lies less than a quarter of a degree south of the celestial equator. In 1900, it was 7 minutes of arc north of the equator. As a result of a shift in the Earth's axial tilt, it crossed over to the Southern Hemisphere in December 1923.
This is an evolved A-type giant star with a stellar classification of A0 III. It has around three times the mass of the Sun and 4.5 times the Sun's radius. The abundance of elements is similar to that in the Sun. It radiates 120 times the solar luminosity from its outer atmosphere at an effective temperature of 9,984 K. Alpha Sextantis is around 295 million years old with a projected rotational velocity of 21 km/s.


Zeta Fornacis

ζ Fornacis (often Latinised as Zeta Fornacis) is the Bayer designation for a star in the southern constellation of Fornax. It is faintly visible to the naked eye with an apparent visual magnitude of 5.67. Based upon a measured annual parallax shift of , it is located at a distance of about 109 light years from the Sun. The star is drifting further away with a radial velocity of +29 km/s. Positioned about 1.3° to the southeast of Zeta Fornacis is the galaxy NGC 1232.
This is an F-type main sequence star with a stellar classification of F4 V. With an estimated age of 1.5 billion years, it has 1.8 times the mass of the Sun and 1.6 times the Sun's radius. The star is radiating 4.77 times the luminosity of the Sun from its photosphere at an effective temperature of 6,699 K. It is spinning with a projected rotational velocity of 84.9 km/s, and has a near-solar metallicity – what astronomers term the abundance of elements other than hydrogen and helium. This star is a probable member of the Hyades Stream – a group of stars that share a common motion through space with the Hyades cluster.
Zeta Fornacis has a common proper motion companion, NLTT 9563, a magnitude 13.50 star with a classification of M 2.5. As of 2004, this companion was positioned at an angular separation of 176.1 arc seconds along a position angle of 288.1°.


NGC 503

NGC 503, also occasionally referred to as PGC 5086 or GC 5169, is an elliptical galaxy in the constellation Pisces. It located approximately 265 million light-years from the Solar System and was discovered on 13 August 1863 by German astronomer Heinrich Louis d'Arrest.
Observation history.
Arrest discovered NGC 503 using an 11" reflecting telescope in Copenhagen. His position matches perfectly with PGC 5086. At the time of discovery, he considered the possibility of having observed one of William Herschels discoveries (NGC 495, 496, 499). John Louis Emil Dreyer, creator of the New General Catalogue, described the galaxy as "extremely faint, extremely small" with a "double star 4 arcmin to southwest".


EE Pegasi

EE Pegasi is a variable triple star system in the northern constellation Pegasus. It is too faint to be readily visible to the naked eye with a combined apparent visual magnitude of 6.96. The system is located at a distance of approximately 472 light years from the Sun based on Parallax, but is drifting closer with a radial velocity of −23 km/s.
This system was found to be an eclipsing binary by German astronomer Cuno Hoffmeister in 1935, and has since been the subject of multiple studies. The pair orbit each other closely with a period of 2.8 days. The magnitude 7.09 primary, component A, is an Am star with a stellar classification of A3m. It has more than double the mass and radius of the Sun. The secondary companion, component B, is an F-type main-sequence star with a class of F5V and a visual magnitude of 9.40. A third component is a smaller orange or red dwarf that orbits the main pair every .


Epsilon Leonis

Epsilon Leonis (ε Leo, ε Leonis) is the fifth-brightest star in the constellation Leo, consistent with its Bayer designation Epsilon. It is known as Algenubi or Ras Elased Australis. Both names mean "the southern star of the lion's head". Australis is Latin for "southern" and Genubi is Arabic for "south".
Properties.
Epsilon Leonis has a stellar classification of G1 II, with the luminosity class of II indicating that, at an age of , it has evolved into a bright giant. It is much larger and brighter than the Sun with a luminosity 288 times and a radius 21 times solar. Consequently, its absolute magnitude is actually –1.49, making it one of the more luminous stars in the constellation, significantly more than Regulus. Its apparent brightness, though, is only 2.98. Given its distance of about , the star is more than three times the distance from the Sun than Regulus. At this distance, the visual magnitude of Epsilon Leonis is reduced by 0.03 as a result of extinction caused by intervening gas and dust.
Epsilon Leonis exhibits the characteristics of a Cepheid-like variable, changing by an amplitude of 0.3 magnitude every few days. It has around four times the mass of the Sun and a projected rotational velocity of . Based upon its iron abundance, the metallicity of this star's outer atmosphere is only around 52% of the Sun's. That is, the abundance of elements other than hydrogen and helium is about half that in the Sun.


Epsilon Pyxidis

Epsilon Pyxidis (ε Pyxidis) is quadruple star system in the southern constellation of Pyxis. It is faintly visible to the naked eye, having a combined apparent visual magnitude of +5.60. Based upon an annual parallax shift of 15.39 mas as seen from Earth, it is located around 212 light years from the Sun. The system is deemed to be a member of the Sirius supercluster of stars that share a common motion through space.
The primary, component A, is a white-hued A-type subgiant star with a stellar classification of A4 IV. It is a microvariable, showing a 0.0056 change in magnitude with a frequency of 0.16245 times per day. Epsilon Pyxidis has been catalogued as an Am star, although this remains uncertain. It has double the mass of the Sun and radiates 19 times the Sun's luminosity from its photosphere at an effective temperature of 6,368 K.
In addition to a close companion of unknown type at an angular separation of 0.17 arc seconds, the primary shares an orbit with a binary star system, components B and C, that lie at an angular separation of 17.8 arc seconds. At the estimated distance of this system, this corresponds to a projected separation of around 1,150 AU. The B/C pair consist of visual magnitude 10.5 and 10.8 stars with a mean separation of 0.3 arc seconds. They have estimated mass of 90% and 95% that of the Sun, respectively.


30 Herculis

30 Herculis is a binary star system in the northern constellation of Hercules. It has the Bayer designation g Herculis, while "30 Herculis" is the Flamsteed designation. This system is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.83. Based upon a measured parallax of , it is located around 354 light years away from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of 1.5 km/s.
This is a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.37. The visible component is an aging red giant on the asymptotic giant branch with a stellar classification of M6- III. According to Samus et al. (2017), it is a semiregular variable of subtype SRb, which ranges between visual magnitudes 4.3 and 6.3 over 89.2 days. It displays cyclical periods of 62.3, 89.5, and 888.9 days. The star is surrounded by a circumstellar dust shell that seems primarily composed of oxides of iron, magnesium, and aluminium, rather than silicates.


Abhijit (nakshatra)

Abhijit () is the 22nd lunar mansion out of 28 in the Indian system of nakshatra.
Abhijit is the Sanskrit name for Vega, the brightest star in the northern constellation of Lyra. Abhijit means "the victorious One" or "the One who cannot be defeated". In the Mahabharata (Harivamsa).
History.
In the Srimad Bhagavatam, Krishna tells Arjuna, that among the Nakshatras he is Abhijit, which remark indicates the auspiciousness of this Nakshatra. In the Bhagavad GitaChapter 10 Verse 21, it is mentioned as Sasi (Moon) rather than as Abhijit.
Its longitude starts from 06° 40' to 10° 53' 20 in sidereal Capricorn i.e. from the last quarter of nakshatra Uttara Ashādhā to first 1/15 th part of Shravana. Hence, Abhijit nakshatra i not a regular nakshatra with four "padas" or quarters and thus it serves as an intercalary asterism most of the time. It is not mentioned as frequently as the other asterisms in mythology.
The Moon or Chandra is said to have 27 (not 28) wives with whom he stays for one day in a sidereal lunar month. Each of the 27 asterisms is feminine: only Abhijit is masculine. Abhijit Nakshatra is an auspicious time in the Hindu Calendar.


Phi2 Lupi

Phi2 Lupi, Latinized from φ2 Lupi, is a solitary star in the southern constellation of Lupus. With an apparent magnitude of 4.535, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 6.28 mas as seen from Earth, it is located around 520 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of due to interstellar dust. It is a member of the Upper Centaurus-Lupus subgroup of the Scorpius–Centaurus Association.
This is an ordinary B-type main sequence star with a stellar classification of B4 V. It has an estimated 6.1 times the mass of the Sun and about 3.4 times the Sun's radius. The star is roughly 40 million years and is spinning with a projected rotational velocity of 141 km/s. It is radiating about 800 times the solar luminosity from its photosphere at an effective temperature of 16,780 K.


NGC 3697

NGC 3697 is a spiral galaxy in the constellation of Leo. It was discovered on 24 February 1827 by John Herschel. It was described as "extremely faint, very small, extended 90°" by John Louis Emil Dreyer, the compiler of the New General Catalogue. It is a member of HCG 53, a compact group of galaxies.


HD 79447

HD 79447 is a single star in the southern constellation of Carina. It has the Bayer designation "i Carinae", while "HD 79447" is the identifier from the "Henry Draper catalogue". This star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of +3.96. It is located at a distance of approximately 540 light years from the Sun based on parallax, and has an absolute magnitude of −2.14. The star drifting further away with a radial velocity of +18 km/s. It is a candidate member of the Lower Centaurus-Crux group of the Sco OB2 association.
This object is a B-type main-sequence star with a stellar classification of B3V. A surface magnetic field has been detected with a strength on the order of . It has an estimated age of around 39 million years with no measured spin rate. The star has about 5.6 times the radius of the Sun and 7 times the Sun's mass. It is radiating over two thousand times the luminosity of the Sun from its photosphere at an effective temperature of 18,900 K.


TOI-755

TOI-755, also known as HD 110113, is a Sun-like star with a distance from the Solar System of about and located in the Centaurus constellation. The discovery by Osborn et al. was published at the Monthly Notices of the Royal Astronomical Society in 2021.
Characteristics.
TOI-755 has been classified as a G-type main-sequence star (yellow dwarf). It has a temperature of , and a solar mass of almost 1, similar to the Sun.
Planetary system.
The two planets that are orbiting TOI-755, TOI-755b and TOI-755c, were suspected since 2021. TOI-755b's temperature is over and TOI-755c's temperature is cooler at around , which means they are Hot Neptunes.


NGC 6709

NGC 6709 is an open cluster in the constellation Aquila.


Gliese 754

Gliese 754 is a dim star in the southern constellation of Telescopium. It has an apparent visual magnitude of 12.25, which requires a telescope to view. The star is located at a distance of 19.3 light-years from the Sun based on parallax, and it is drifting further away with a radial velocity of +7 km/s. It is one of the hundred closest stars to the Solar System. Calculations of its orbit around the Milky Way showed that it is eccentric, and indicate that it might be a thick disk object.
The stellar classification of Gliese 754 is M4V, indicating that this is a small red dwarf star on the core hydrogen fusing main sequence. It has 17% of the mass of the Sun and 21% of the Sun's radius. The star is fully convective and is a source of X-ray emission. It is rotating slowly with a period of about 133 days. The metallicity is sub-solar, indicating it has a lower abundance of heavy elements compared to the Sun. It is radiating just 0.5% of the luminosity of the Sun from its photosphere at an effective temperature of around 3,202 K.
Planetary System.
In June 2019 a candidate exoplanet was reported in orbit around Gliese 754. It was detected using the Doppler method and is orbiting at a distance of with a period of 78 days. The orbit is essentially circular, to within the margin of error. The habitable zone for this star ranges from to ; inside the orbit of this proposed companion.


78 Cancri

78 Cancri is a star in the zodiac constellation of Cancer, located 548 light years from the Sun. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.19. The star is moving away from the Earth with a relatively large radial velocity of +77.7 km/s. It is an evolved giant star with a stellar classification of K3 III.


VW Cephei

VW Cephei (VW Cep) is an eclipsing contact binary of W Ursae Majoris-type located roughly at 90.6 light years from the Sun, whose two component stars share a common outer layer. Because the two components share their outer layers, as the components of W Ursae Majoris do, they have the same stellar classification, and are classified as yellow G-type main sequence dwarfs. The components take 0.2783 days (roughly 6.7 hours) to revolve around a common barycentre. Orbital period variations suggest the presence of one more additional perturbing objects of likely low-mass stellar nature.
Unseen companion(s).
Orbital period variations suggest the presence of one more perturbing unseen object around the eclipsing binary. Several publications have tried to set constrains to putative orbital period and minimum mass for unseen component. The most recent article proposes an orbital period of 29.8 years for a stellar object with roughly three fourths the Sun's mass and high orbital eccentricity (e=0.66). Inclination is assumed being 33.6 degrees.
Nevertheless, hints of an additional body in the system still subsist and the authors infer a period of 77.46 years and eccentricity of 0.54 for unseen fourth component. Minimum mass is unclear, tentatively assumed being as small as 0.19 solar masses, as inferred by Pribulla et al. in 2000. In any case orbital solutions are still blurry and further calculations are needed to provide a more robust model.
With the release of Gaia DR2, the presence of any stellar companions was ruled out.


Net (Chinese constellation)

The Net mansion () is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger.


NGC 6340

NGC 6340 is an unbarred spiral galaxy in the constellation Draco. The galaxy is approximately 55 million light years away.


Cartwheel Galaxy

The Cartwheel Galaxy (also known as ESO 350-40 or PGC 2248) is a lenticular galaxy and ring galaxy about 500 million light-years away in the constellation Sculptor. It is an estimated 150,000 light-years diameter, and has a mass of about solar masses; its outer ring has a circular velocity of .
It was discovered by Fritz Zwicky in 1941. Zwicky considered his discovery to be "one of the most complicated structures awaiting its explanation on the basis of stellar dynamics."
An estimation of the galaxy's span resulted in a conclusion of 150,000 light years, which is a moderate amount smaller than the Milky Way.
The large Cartwheel galaxy is the dominant member of the Cartwheel galaxy group, which consists of four physically associated spiral galaxies. The three companions are referred to in several studies as G1 - the smaller irregular blue Magellanic spiral, G2 - the yellow compact spiral with a tidal tail, and G3 - a more distant spiral often seen in wide field images.
Structures.
The structure of the Cartwheel galaxy is noted to be extremely complicated and heavily disturbed. The Cartwheel consists of two rings - the outer blue ring, the site of massive ongoing star formation due to gas and dust compression, and the inner yellow nucleic ring that surrounds the galactic center. A ring of dark absorbing dust is also present in the nucleic ring. Several optical arms or “spokes” are seen connecting the outer ring to the inner, and are theorized to be reforming spiral arms following the collision. Observations show the presence of both non-thermal radio and optical spokes, but the two do not overlap and have been shown to be unassociated with each other and thus are different structures.
Evolution.
The galaxy was once a normal spiral galaxy before it apparently underwent a head-on “bullseye” style collision with a smaller companion approximately 2-300 million years prior to how we see the system today. When the nearby galaxy passed through the Cartwheel Galaxy, the force of the collision caused a powerful gravitational shock wave to expand through the galaxy, like a rock being tossed into a sandbed. Moving at high speed, the shock wave swept up and compressed gas and dust, creating a starburst around the galaxy's center portion that were unscathed as it expanded outwards. This explains the bluish ring around the center, brighter portion. It can be noted that the galaxy is beginning to retake the form of a normal spiral galaxy, with arms spreading out from a central core. These arms are often referred to as the cartwheels “spokes”.
Alternatively, a model based on the gravitational Jeans instability of both axisymmetric (radial) and nonaxisymmetric (spiral) small-amplitude gravity perturbations allows an association between growing clumps of matter and the gravitationally unstable axisymmetric and nonaxisymmetric waves which take on the appearance of a ring and spokes. Based on observational data, however, this theory of ring galaxy evolution does not appear to apply to this specific galaxy.
While most images of the Cartwheel display three galaxies close together, a fourth physically associated companion (also known as G3) is known to be associated with the group through an HI tail that connects G3 to the cartwheel. Due to the presence of the HI tail, it is widely believed that G3 is the “bullet” galaxy that plunged through the disk of the cartwheel, creating its current shape, not G1 or G2. This hypothesis makes sense given the size and predicted age of the current structure (~300 million years old as mentioned before). Considering how close G1 and G2 are to the Cartwheel still, it is much more widely believed that the roughly 88 kpc (~287,000 light years) distant G3 is the intruding galaxy.
Neutral hydrogen tail mapping is extremely useful in determining “culprit” galaxies in similar cases where the answer is relatively unclear. Hydrogen gas, being the lightest and most abundant gas in galaxies, is easily torn away from parent galaxies through gravitational forces. Evidence of this can be seen in the Jellyfish Galaxy and the Comet Galaxy, which are undergoing a type of gravitational effect called ram pressure stripping, and other galaxies with tidal tails and star forming stellar streams associated with collisions and mergers. Ram pressure stripping will almost always cause "trailing-dominant" tails of HI gas as a galaxy infalls into a galaxy cluster, while mergers and collisions like the cartwheel often create "leading-dominant" tails as the culprit galaxy’s gravity attracts and pulls on the victim galaxy’s gas in the direction of the culprits motion.
The existing structure of the cartwheel is expected to disintegrate over the next few hundred million years as the remaining gas, dust and stars that hasn’t escaped the galaxy begins to infall back towards the center. It is likely that the galaxy will regain a spiral shape after the infall process completes and spiral density waves have a chance to reform. This is only possible if companions G1, G2 and G3 remain distant and do not undergo an additional collision with the cartwheel.
X-ray sources.
The unusual shape of the Cartwheel Galaxy may be due to a collision with a smaller galaxy such as those in the lower left of the image. The most recent star burst (star formation due to compression waves) has lit up the Cartwheel rim, which has a diameter larger than the Milky Way. Star formation via starburst galaxies, such as the Cartwheel Galaxy, results in the formation of large and extremely luminous stars. When massive stars explode as supernovas, they leave behind neutron stars and black holes. Some of these neutron stars and black holes have nearby companion stars, and become powerful sources of X-rays as they pull matter off their companions (also known as ultra and hyperluminous X-ray sources). The brightest X-ray sources are likely black holes with companion stars, and appear as the white dots that lie along the rim of the X-ray image. The Cartwheel contains an exceptionally large number of these black hole binary X-ray sources, because many massive stars formed in the ring.


Omega Lupi

Omega Lupi, Latinized from ω Lupi, is a double star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.33, showing up as a red-hued star just to the south of Gamma Lupi. Based upon an annual parallax shift of 8.97 mas as seen from Earth, it is located around 360 light years from the Sun.
As of 2007, the components of this system had an angular separation of 11.4 arc seconds along a position angle of 29°, and are most likely gravitationally bound as a wide binary star system. The primary component is a magnitude 4.48 evolved giant star with a stellar classification of K4.5 III. The measured angular diameter, after correction for limb darkening, is . At the estimated distance of Omega Lupi, this yields a physical size of about 40 times the radius of the Sun. The companion is a magnitude 11.0 star.
References.
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HD 220035

HD 220035 is variable star in the equatorial constellation of Aquarius.


HR 3407

HR 3407 is a single star in the southern constellation of Vela. It has the Bayer designation C Velorum; "HR 3407" is the designation in the "Bright Star Catalogue". It is an orange-hued star that is dimly visible to the naked eye with an apparent visual magnitude of 5.01. The distance to this object is approximately 1,040 light years based on parallax measurements, and it is drifting further away with a radial velocity of 4 km/s.
This object is an aging K-type supergiant star with a stellar classification of K1.5Ib. It has about three times the mass of the Sun and has expanded to around 71 times the Sun's radius. The latter is equivalent to , or about one third the distance from the Sun to the Earth. It is spinning with a projected rotational velocity of 4.1. The star displays microvariability with a period of 10.99 cycles per day and an amplitude of 0.0036 in magnitude. It is radiating around 1,600 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,324 K.


Iota Normae

The Bayer designation ι Normae, which is Latinized as Iota Normae and abbreviated ι Nor, is shared by two stars in the southern constellation of Norma:
The pair form a double star that can be viewed with a small telescope.


Psi7 Aurigae

Psi7 Aurigae, Latinized from ψ7 Aurigae, is a star in the northern constellation of Auriga. It is a dim, naked eye star with an apparent visual magnitude of 5.02. Based upon Gaia Data Release 2 parallax values, it is approximately from Earth.
ψ7 Aurigae is a giant star with a stellar classification of K3 III. The measured angular diameter of this star, after correction for limb darkening, is . At its estimated distance, this yields a physical size of about 24 times the radius of the Sun. The outer envelope has an effective temperature of 4,300, giving it an orange colour and a classification as a K-type star. Although cooler than the sun, its larger size means that it is more luminous, emitting in total 217 times as much electromagnetic radiation.
References.
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23 Librae

23 Librae (23 Lib) is a star in the zodiac constellation Libra, making it visible from most of the Earth's surface. With an apparent visual magnitude of 6.45, it requires dark skies and good seeing conditions to see this star with the naked eye. It has a planetary system with two confirmed extrasolar planets.
Properties.
Based upon parallax measurements, this star is located at a distance of from the Earth. The spectral properties of 23 Librae identify it as stellar class G5 V, with the luminosity class of 'V' indicating that this is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. This energy is being radiated from the outer envelope at an effective temperature of about 5,585 K, giving it the yellow hue typical of G-type stars. Estimates of the age of 23 Librae range from 8.4 to 11.1 billion years, making it much older than the Sun.
23 Librae is slightly larger than the Sun, with an estimated 107% of the Sun's mass and 125% of the Sun's radius. The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is higher than in the Sun. It appears to be rotating slowly, with the projected rotational velocity of 2.2 km∙s−1 giving a lower bound to the actual azimuthal velocity along the equator.
Planetary system.
In November 1999 an exoplanet 23 Librae b was announced orbiting 23 Librae, and in 2009 an additional planet was detected. Examination of the system in the infrared using the Spitzer Space Telescope did not reveal any excess emission, which might otherwise suggest the presence of a circumstellar debris disk of orbiting dust. In the popular franchise Halo the star system is home to the planets "Hesiod" farther away from the star and "Madrigal" in the habitable zone.


32 Ophiuchi

32 Ophiuchi is a single star located 410 light years away from the Sun in the constellation Hercules. It is visible to the naked eye as a dim, red-hued star with an apparent visual magnitude of 4.97. This is an aging red giant star on the asymptotic giant branch with a stellar classification of M3−III. Having exhausted the supply of hydrogen at its core it has expanded to 60 times the girth of the Sun. The star is radiating 614 times the luminosity of the Sun from its swollen photosphere at an effective temperature of around 3,712 K. It is moving further away from the Sun with a heliocentric radial velocity of +43 km/s.