Kappa Cephei

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.

Kappa Cephei
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[1] mas
Distance323 ± 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[6] mas
Distance326.2 ± 0.9 ly
(100.0 ± 0.3 pc)
Details
Kap Cep A
Mass3.02±0.5[7] M☉
Radius4.45±0.22[8] R☉
Luminosity191[4] L☉
Surface gravity (log g)3.66±0.03[8] cgs
Temperature10,174±55[8] K
Metallicity [Fe/H]−0.05[4] dex
Age302+77
−72[7] Myr
Kap Cep B
Radius1.32[6] R☉
Luminosity4.05[6] L☉
Temperature7119[6] K
Other designations
κ Cep, 1 Cephei, BD+77°764, HD 192907, HIP 99255, HR 7750, SAO 9665, GSC 04589-03106[9]
Database references
SIMBADdata
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
  1. 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.
  2. 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 (5th Revised ed.). 5050. Bibcode:1995yCat.5050....0H.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. "kap Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-11.
  10. 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.
  11. 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.
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