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.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 | |
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]
References
edit- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c Hoffleit, D.; Warren, W. H. (1995). "VizieR On-line Data Catalog: Bright Star Catalogue". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050 (5th Revised ed.). Bibcode:1995yCat.5050....0H.
- ^ a b c Murphy, R. E. (1969). "A spectroscopic investigation of visual binaries with B-type primaries". The Astronomical Journal. 74: 1082. Bibcode:1969AJ.....74.1082M. doi:10.1086/110908.
- ^ a b c Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications. 30: 57. Bibcode:1967IAUS...30...57E.
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637x/804/2/146. S2CID 33401607.
- ^ a b c Fitzpatrick, E. L.; Massa, D. (March 2005). "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry". The Astronomical Journal. 129 (3): 1642–1662. arXiv:astro-ph/0412542. Bibcode:2005AJ....129.1642F. doi:10.1086/427855. S2CID 119512018.
- ^ "kap Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-11.
- ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- ^ a b c Mason, Brian D.; et al. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.