Xi Cephei

ξ Cephei
Location of ξ Cephei (circled)
Observation data
Epoch J2000      Equinox ICRS
Constellation Cepheus
A
Right ascension 22h 03m 47.440s
Declination +64° 37′ 40.70″
Apparent magnitude (V) 4.45 (4.61 + 6.50)‍
B
Right ascension 22h 03m 46.217s
Declination +64° 37′ 41.47″
Apparent magnitude (V) 6.34
Characteristics
A
Spectral type kA2.5hF2mF2(IV) (A3Vm + F2III)‍
B
Evolutionary stage main sequence
Spectral type F8V
Astrometry
A
Radial velocity (Rv)−7.2±2 km/s
Proper motion (μ) RA: +212.563 mas/yr
Dec.: +89.058 mas/yr
Parallax (π)32.12±0.8066 mas
Distance102 ± 3 ly
(31.1 ± 0.8 pc)
B
Radial velocity (Rv)−6.2±2 km/s
Proper motion (μ) RA: +202.094 mas/yr
Dec.: +81/933 mas/yr
Parallax (π)32.1835±0.0184 mas
Distance101.34 ± 0.06 ly
(31.07 ± 0.02 pc)
Orbit
Period (P)2.245+0.001
−0.000 years
Semi-major axis (a)0.072+0.000
−0.001″
Eccentricity (e)0.460+0.009
−0.008
Inclination (i)67.447+0.508
−0.443°
Longitude of the node (Ω)272.995+0.702
−0.301°
Periastron epoch (T)1968.751+7
−5
Argument of periastron (ω)
(secondary)		90.354+0.315
−0.418°
Semi-amplitude (K1)
(primary)		7.81 km/s
Semi-amplitude (K2)
(secondary)		19.98 km/s
Details
Aa
Mass1.721+0.134
−0.120 M☉
Luminosity6.6 L☉
Temperature7,943 K
Age200 Myr
Ab
Mass0.512 M☉
Luminosity1.8 L☉
Temperature6,310 K
Age525 Myr
B
Mass1.14 M☉
Radius1.28 R☉
Luminosity2.08 L☉
Surface gravity (log g)4.26 cgs
Temperature6,123 K
Age3.98 Gyr
Other designations
Kurhah, 17 Cephei, BD+63°1802, HIP 108917, HR 8417, SAO 19827, CCDM J22038+2407, WDS J22038+6438
A: HD 209790
B: HD 209791
Database references
SIMBADξ
A
B

Xi Cephei is a multiple star system in the northern constellation of Cepheus. Its name is a Bayer designation. This system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 4.29. Based on parallax measurements, it is located at a distance of approximately 102 light-years from Earth.

This system consists of a binary pair, designated Xi Cephei A, together with a more distant companion, Xi Cephei B. A's two components are themselves designated Xi Cephei Aa (officially named Kurhah /ˈkɜːrhə/, the traditional name of the system) and Ab.

Nomenclature

ξ Cephei, Latinized to Xi Cephei, is the system's Bayer designation. It is abbreviated Xi Cep or ξ Cep. The designations of the three constituents as ξ Cephei A, B and C, and those of A's components – ξ Cephei Aa and Ab – derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).

Xi Cephei bore the traditional names Kurhah, Alkirdah or Al Kirduh, the name coming from Qazvini who gave Al Ḳurḥaḥ (القرحة al-qurhah), an Arabic word Ideler translated as a white spot, or blaze, in the face of a horse. Allen indicates that Ideler felt this was not a proper name for a star, and suggested the name Al Ḳirdah (ألقردة al qírada "the Ape"). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name Kurhah for the component Xi Cephei Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.

In Chinese, 天鈎 (Tiān Gōu), meaning Celestial Hook, refers to an asterism consisting of Xi Cephei, 4 Cephei, HD 194298, Eta Cephei, Theta Cephei, Alpha Cephei, 26 Cephei, Iota Cephei and Omicron Cephei. Consequently, the Chinese name for Xi Cephei itself is 天鈎六 (Tiān Gōu liù, English: the Sixth Star of Celestial Hook).

Properties

Xi Cephei A is a double-lined spectroscopic binary system with an orbital period of 820 days and an eccentricity of 0.5. The primary, component Aa, is a chemically peculiar Am star with an apparent magnitude of +4.61. The spectroscopic secondary, component Ab, is an F-type star.

Eight arcseconds away from Xi Cephei A, Xi Cephei B is a 6th-magnitude main sequence star.

Xi Cephei C is a 13th magnitude star nearly two arcminutes away. It has a small parallax and is an unrelated background star only accidentally in line with Xi Cephei.

Notes

  1. ↑ from primary mass and mass ratio

References

  1. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ↑ Fabricius, C.; et al. (2002). "The Tycho double star catalogue". Astronomy and Astrophysics. 384: 180. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822.
  3. 1 2 3 4 Tokovinin, Andrei (2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv:1712.04750. Bibcode:2018ApJS..235....6T. doi:10.3847/1538-4365/aaa1a5.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  5. ↑ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355. Bibcode:2000A&A...355L..27H.
  6. ↑ Gray, R. O; Garrison, R. F (1989). "The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation". The Astrophysical Journal Supplement Series. 69: 301. Bibcode:1989ApJS...69..301G. doi:10.1086/191315.
  7. ↑ Gray, R. O; et al. (2001). "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars". The Astronomical Journal. 121 (4): 2148. Bibcode:2001AJ....121.2148G. doi:10.1086/319956.
  8. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
  9. 1 2 3 Videla, Miguel; et al. (April 2022). "Bayesian Inference in Single-line Spectroscopic Binaries with a Visual Orbit". The Astronomical Journal. 163 (5): 220. arXiv:2203.07438. Bibcode:2022AJ....163..220V. doi:10.3847/1538-3881/ac5ab4. ISSN 1538-3881.
  10. 1 2 3 Farrington, C. D.; et al. (2014). "Separated Fringe Packet Observations with the CHARA Array. II. omega Andromeda, HD 178911, and xi Cephei". The Astronomical Journal. 148 (3): 48. arXiv:1407.0639. Bibcode:2014AJ....148...48F. doi:10.1088/0004-6256/148/3/48. S2CID 12909818.
  11. 1 2 3 4 5 6 Piccotti, Luca; et al. (2020). "A study of the physical properties of SB2s with both the visual and spectroscopic orbits". Monthly Notices of the Royal Astronomical Society. 492 (2): 2709. Bibcode:2020MNRAS.492.2709P. doi:10.1093/mnras/stz3616.
  12. ↑ "xi. Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-02-01.
  13. ↑ Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". Journal of the American Association of Variable Star Observers (Jaavso). 42 (2): 443. Bibcode:2014JAVSO..42..443M.
  14. 1 2 "Naming Stars". IAU.org. Archived from the original on 11 April 2020. Retrieved 16 December 2017.
  15. ↑ Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  16. ↑ "Islamic Crescent Project: Star names". Archived from the original on 2008-02-02. Retrieved 2010-12-08.
  17. ↑ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 159. ISBN 0-486-21079-0. Retrieved 2010-12-12.{{cite book}}: CS1 maint: ignored ISBN errors (link)
  18. ↑ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. Archived from the original on 10 June 2016. Retrieved 22 May 2016.{{cite web}}: CS1 maint: postscript (link)
  19. ↑ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Archived from the original (PDF) on 2022-10-09. Retrieved 2018-07-14.
  20. ↑ (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.
  21. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived January 29, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  22. ↑ 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.
  23. ↑ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.