21 Aquilae
21 Aquilae is a solitary variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; "21 Aquilae" is its Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of 5.14. The star is located at a distance of around from Earth, give or take a 30 light-year margin of error. It is moving closer to the Earth with a heliocentric radial velocity of –5 km/s.

The stellar classification of this star is B8 II-III, with the luminosity class of II-III suggesting that the spectrum displays elements of both a giant star and a bright giant. It is a chemically peculiar star of the Mercury-Manganese type (CP3). This is a probable Alpha2 Canum Venaticorum variable that ranges in visual magnitude from 5.06 down to 5.16. The star is radiating 913 times the luminosity of the Sun from its photosphere at an effective temperature of 13,175 K; this searing heat gives it the blue-white glow of a B-type star.

21 Aquilae is catalogued as an optical double star, having a 12th magnitude companion away as of 2010. It was first identified as a double star by John Herschel. The companion is a distant background object.
Q6243
variable star
Concept
Q187646
equatorial
Concept
Q8928
constellation
Concept
Q10586
Aquila
CEL
Q593448
variable star designation
Concept
Q111116
Flamsteed designation
Concept
Q124313
apparent visual magnitude
Concept
Q1352827
margin of error
Concept
Q240105
radial velocity
Concept
Q25377588
stellar classification
Concept
Q25377588
luminosity class
Concept
Q752171
spectrum
Concept
Q5875
giant star
Concept
Q5881
bright giant
Concept
Q1142192
chemically peculiar star
Concept
Q1140275
Mercury-Manganese type
Concept
Q1141942
Alpha2 Canum Venaticorum variable
CEL
Q843877
luminosity of the Sun
Concept
Q6372
photosphere
Concept
Q854050
effective temperature
Concept
Q25377588
B-type star
Concept
Q13890
optical double
Concept
Q14278
John Herschel
PER
Q2608320
21 Aquilae
CEL
Q2608320
21 Aquilae
CEL
Q2608320
21 Aquilae
CEL
2010-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2010
DATE
+21^^http://www.w3.org/2001/XMLSchema#decimal
21
NUMBER
+1288^^http://www.w3.org/2001/XMLSchema#decimal
1288
NUMBER
+21^^http://www.w3.org/2001/XMLSchema#decimal
21
NUMBER
+5.14^^http://www.w3.org/2001/XMLSchema#decimal
5.14
NUMBER
+30^^http://www.w3.org/2001/XMLSchema#decimal
30
NUMBER
+5^^http://www.w3.org/2001/XMLSchema#decimal
5
NUMBER
+8^^http://www.w3.org/2001/XMLSchema#decimal
8
NUMBER
+3^^http://www.w3.org/2001/XMLSchema#decimal
3
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+5.06^^http://www.w3.org/2001/XMLSchema#decimal
5.06
NUMBER
+5.16^^http://www.w3.org/2001/XMLSchema#decimal
5.16
NUMBER
+21^^http://www.w3.org/2001/XMLSchema#decimal
21
NUMBER
+12^^http://www.w3.org/2001/XMLSchema#decimal
12
NUMBER
constellation
type of variable star
instance of
subclass of
subclass of