Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Cepheus |
Right ascension | 20h 08m 53.34492s[1] |
Declination | +77° 42′ 41.0909″[1] |
Apparent magnitude (V) | 4.39[2] |
Characteristics | |
Spectral type | B9III + A7V[3] |
U−B color index | -0.11[2] |
B−V color index | -0.05[2] |
Astrometry | |
Absolute magnitude (MV) | −0.54[4] |
Kap Cep A | |
Radial velocity (Rv) | −22.8±0.9[5] km/s |
Proper motion (μ) | RA: +12.044[1] mas/yr Dec.: +26.199[1] mas/yr |
Parallax (π) | 10.0861 ± 0.2468 mas[1] |
Distance | 323 ± 8 ly (99 ± 2 pc) |
Kap Cep B | |
Radial velocity (Rv) | −15.3±5[5] km/s |
Proper motion (μ) | RA: +10.725±0.047[6] mas/yr Dec.: +25.543±0.056[6] mas/yr |
Parallax (π) | 9.9981 ± 0.0290 mas[6] |
Distance | 326.2 ± 0.9 ly (100.0 ± 0.3 pc) |
Details | |
Kap Cep A | |
Mass | 3.02±0.5[7] M☉ |
Radius | 4.45±0.22[8] R☉ |
Luminosity | 191[4] L☉ |
Surface gravity (log g) | 3.66±0.03[8] cgs |
Temperature | 10,174±55[8] K |
Metallicity [Fe/H] | −0.05[4] dex |
Age | 302+77 −72[7] Myr |
Kap Cep B | |
Radius | 1.32[6] R☉ |
Luminosity | 4.05[6] L☉ |
Temperature | 7119[6] K |
Other designations | |
Database references | |
SIMBAD | data |
B | |
C |
Kappa Cephei, Latinized from κ Cephei, is a binary star[10] system in the northern circumpolar constellation of Cepheus. It is visible to the naked eye as a faint, blue white-hued point of light with an apparent visual magnitude is 4.39.[11] The system is located approximately 323–326 light years distant from the Sun, based on parallax.
The two gravitationally-bound members of this system had an angular separation of 7.3″ along a position angle of 120°, as of 2015.[11] The primary, designated component A, has a stellar classification of B9III,[3] matching a blue giant. The magnitude 8.34 secondary, component B, is an A-type main-sequence star of class A7V.[3] A third star of 10th magnitude, BD+77 763, is listed as component C in the Washington Double Star Catalog although it is a background object unrelated to the other two. [11]
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