Theta Cephei

From the Science Archives, the open-project database of science information
Jump to navigation Jump to search
Theta Cephei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cepheus
Right ascension 22h 26m 42.40624s[1]
Declination +78° 47′ 09.0725″[1]
Apparent magnitude (V) 4.22[2]
Characteristics
Spectral type A7 III[3]
U−B color index +0.16[2]
B−V color index +0.20[2]
Astrometry
Proper motion (μ) RA: −13.33[1] mas/yr
Dec.: −36.95[1] mas/yr
Parallax (π)15.83 ± 0.23[1] mas
Distance206 ± 3 ly
(63.2 ± 0.9 pc)
Absolute magnitude (MV)+1.12[4]
Orbit[5]
Period (P)840.6 d
Eccentricity (e)0.03
Periastron epoch (T)2416214.5 JD
Argument of periastron (ω)
(secondary)
83.7°
Semi-amplitude (K1)
(primary)
13.9 km/s
Details
θ Cep A
Luminosity28[6] L
Surface gravity (log g)3.74[3] cgs
Temperature7,816[3] K
Metallicity [Fe/H]+0.27±0.04[4] dex
Rotational velocity (v sin i)52.0[3] km/s
Other designations
θ Cep, 2 Cep, BD+62° 1821, FK5 767, HD 195725, HIP 101093, HR 7850, SAO 18897[7]
Database references
SIMBADdata

Theta Cephei, Latinized from θ Cephei, is a stellar class A7, fourth-magnitude star in the constellation Cepheus. It is a white-hued, single-lined spectroscopic binary system, located about 206 light-years from Earth. The pair have an orbital period of 840.6 days with a low eccentricity of 0.03.[5] Shared with η Cep, this star system has the title Al Kidr.[8]

In Chinese, 天鈎 (Tiān Gōu), meaning Celestial Hook, refers to an asterism consisting of 4 Cephei, HD 194298, η Cephei, α Cephei, ξ Cephei, 26 Cephei, ι Cephei and ο Cephei.[9] Consequently, θ Cephei itself is known as 天鈎三 (Tiān Gōu sān, English: the Third Star of Celestial Hook.).[10]

References[edit]

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode 2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 2.0 2.1 2.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode 1966CoLPL...4...99J.
  3. 3.0 3.1 3.2 3.3 Takeda, Yoichi et al. (April 2012), "Lithium, Sodium, and Potassium Abundances in Sharp-Lined A-Type Stars", Publications of the Astronomical Society of Japan 64 (2): 15, arXiv:1111.1603, Bibcode 2012PASJ...64...38T, doi:10.1093/pasj/64.2.38, 38
  4. 4.0 4.1 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. 5.0 5.1 Pourbaix, D. et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics 424 (2): 727, arXiv:astro-ph/0406573, Bibcode 2004A&A...424..727P, doi:10.1051/0004-6361:20041213.
  6. McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, arXiv:1208.2037, Bibcode 2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  7. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  8. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  9. (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  10. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 6 日


Add your comment
The Science Archives welcomes all comments. If you do not want to be anonymous, register or log in. It is free.


As a reminder, article comments are only for discussions on how to improve the article. Please direct other comments to a user's talk page. Please be formal and do not use excessive uppercase. Please be advised you may receive an automatic block if you break the article comments policy. For information regarding what is acceptable/not acceptable in article comments, please message Icons-flag-ru.png Joey (talk), Natalia (talk), Icons-flag-fr.png ynoss (talk), or Icons-flag-ca.png Daniel (older account/talk).