Nu Centauri
Nu Centauri, Latinized from ν Centauri, is a binary star system in the southern constellation of Centaurus. The combined apparent visual magnitude of the pair is +3.41, making this one of the brightest members of the constellation. Based upon parallax measurements made during the Hipparcos mission, this star system is located at a distance of roughly from Earth. The margin of error for this distance is about 2%, which is enough to give an error in distance of ±10 light years.

This is a single-lined spectroscopic binary system, which means that the two stellar components have not been individually resolved with a telescope. Instead, their orbital motion can be tracked through periodic shifts in the spectrum of the primary. The gravitational perturbation of the hidden secondary component upon the primary is causing the latter to first move toward and then away from the Earth, creating Doppler shift changes in the spectrum. From these subtle shifts, the orbital elements of the pair can be extracted. The pair are orbiting their common center of mass in a circular orbit with a period of only 2.622 days, indicating that they are in a relatively tight orbit.

The interaction between the two components of this system appears to be creating emission lines in the spectrum, turning the primary into a Be star. It has a stellar classification of B2 IV, which matches a massive B-type subgiant star. The primary has 8.5 times the mass of the Sun and 6.4 times the Sun's radius. It is a Beta Cephei type variable star with a brightness that periodically varies from magnitude +3.38 to +3.41 over an interval of 0.17 days. The tidal interaction with the secondary component has turned it into a rotating ellipsoidal variable.

This star system is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius-Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.
Q466126
Latinized
ORG
Q50053
binary star
Concept
Q8928
constellation
Concept
Q8844
Centaurus
CEL
Q124313
apparent visual magnitude
Concept
Q1063553
brightest members
UNK
Q165074
parallax
Concept
Q555846
Hipparcos
MISC
Q1352827
margin of error
Concept
Q50053
spectroscopic binary
Concept
Q76436
Doppler shift
Concept
Q272626
orbital element
Concept
Q212111
emission line
Concept
Q812800
Be star
Concept
Q25377588
stellar classification
Concept
Q6227
subgiant star
Concept
Q764463
Beta Cephei type
CEL
Q6243
variable star
Concept
Q1332364
rotating ellipsoidal variable
Concept
Q193223
proper motion
Concept
Q45059
Scorpius-Centaurus
CEL
Q736194
OB association
Concept
Q2358189
Nu Centauri
CEL
++3.41^^http://www.w3.org/2001/XMLSchema#decimal
+3.41
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+10^^http://www.w3.org/2001/XMLSchema#decimal
10
NUMBER
+2.622^^http://www.w3.org/2001/XMLSchema#decimal
2.622
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+8.5^^http://www.w3.org/2001/XMLSchema#decimal
8.5
NUMBER
+6.4^^http://www.w3.org/2001/XMLSchema#decimal
6.4
NUMBER
++3.38^^http://www.w3.org/2001/XMLSchema#decimal
+3.38
NUMBER
++3.41^^http://www.w3.org/2001/XMLSchema#decimal
+3.41
NUMBER
+0.17^^http://www.w3.org/2001/XMLSchema#decimal
0.17
NUMBER
constellation
instance of
type of variable star
instance of