Kappa Andromedae
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Star Kappa Andromedae |
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| AladinLite | |||||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Andromeda | ||||||||||||||||||
| Right ascension | 23 h 40 m 24.5 s | ||||||||||||||||||
| declination | + 44 ° 20 ′ 0.2 ″ | ||||||||||||||||||
| Apparent brightness | 4.14 mag | ||||||||||||||||||
| Typing | |||||||||||||||||||
| B − V color index | −0.067 | ||||||||||||||||||
| U − B color index | −0.221 | ||||||||||||||||||
| Spectral class | B9 IVn | ||||||||||||||||||
| Astrometry | |||||||||||||||||||
| Radial velocity | −15.0 km / s | ||||||||||||||||||
| parallax | 19.37 ± 0.19 mas | ||||||||||||||||||
| distance | 168 ± 2 ly 51.6 ± 0.5 pc |
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| Proper movement | |||||||||||||||||||
| Rec. Share: | 80.73 mas / a | ||||||||||||||||||
| Dec. portion: | −18.70 mas / a | ||||||||||||||||||
| Physical Properties | |||||||||||||||||||
| Dimensions | 2.8 +0.1−0.2 M ☉ | ||||||||||||||||||
| radius | 2.29 ± 0.06 R ☉ | ||||||||||||||||||
| Luminosity |
78.5 L ☉ |
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| Effective temperature | 11 361 ± 66 K | ||||||||||||||||||
| Rotation time | 176 km / s | ||||||||||||||||||
| Age | 220 ± 100 million a | ||||||||||||||||||
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Other names and catalog entries |
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Kappa Andromedae (short: κ And, κ Andromedae) is a star in the constellation Andromeda .
properties
The spectral class of Kappa Andromedae is B9 IVn. This makes the star a sub-giant that develops away from the main sequence into a giant star . The size of Kappa Andromedae is 2.3 solar radii and it has a high rotational speed of 176 km / s. The surface is over 11,000 K, so the star glows white-bluish.
The apparent magnitude of Kappa Andromedae is 4.1 mag. This means that, according to the Bortle scale , the star is visible to the naked eye outside of heavily lit cities. Parallax measurements by Hipparcos estimate the distance of Kappa Andromedae from Earth to be 168 light years (52 parsecs ).
Companion Kappa Andromedae b
In November 2012, a young, hot Super-Jupiter with about 12.8 Jupiter masses , which is slightly larger than Jupiter , was discovered through direct observation. The planet orbits the star at a distance of 55 ± 2 AU . The temperature was estimated at 1700 K and the age at 30 million years. The object is known as the Kappa Andromedae b .
In September 2013, the estimated mass was corrected to 37 to 66 Jupiter's masses by reassessing the age of the star, making it no longer a planet, but a brown dwarf . Since its creation, Kappa Andromedae b shines reddish, whereby it cools down over time.