Xi1 Ceti
Location of ξ1 Ceti (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cetus
Right ascension 02h 12m 59.99769s[1]
Declination +08° 50′ 48.2023″[1]
Apparent magnitude (V) +4.36[2] [combined]
Characteristics
Spectral type G7III Ba0.4 Fe-1[3] + DA4[4]
B−V color index 0.878±0.024[2]
Astrometry
Radial velocity (Rv)−3.93±0.09[2] km/s
Proper motion (μ) RA: −24.498[1] mas/yr
Dec.: −5.952[1] mas/yr
Parallax (π)9.5451 ± 0.3275 mas[1]
Distance340 ± 10 ly
(105 ± 4 pc)
Absolute magnitude (MV)–0.99[5]
Orbit[6]
Period (P)1,642.1±1.3
Semi-major axis (a)≥ 0.896 ± 0.020 AU (134 ± 3 Gm)
Eccentricity (e)0 (fixed)
Periastron epoch (T)34,985±5 MJD
Semi-amplitude (K1)
(primary)		5.91±0.14 km/s
Details
A
Mass3.80[5] M☉
Radius18.2+1.0
−2.4[1] R☉
Luminosity209.9±8.2[1] L☉
Surface gravity (log g)2.60[1] cgs
Temperature5,184±50[5] K
Metallicity [Fe/H]−0.01[5] dex
Age100[7] Myr
B
Mass0.8[5] M☉
Surface gravity (log g)8.4[8] cgs
Other designations
ξ1 Cet, ksi01 Cet, 65 Ceti, NSV 749, BD+08° 345, HD 13611, HIP 10324, HR 649, SAO 110408, WDS 02130+0851, WD 02130+0851[9]
Database references
SIMBADdata
Exoplanet Archivedata

Xi1 Ceti , Latinized from ξ1 Ceti, is a binary star[10] system located in the equatorial constellation of Cetus. It is visible to the naked eye with a combined apparent visual magnitude of +4.36.[2] The distance to this system is approximately 340 light years based on parallax measurements, and it is drifting closer to the Sun with a radial velocity of −4 km/s.[2] The proximity of the star to the ecliptic means it is subject to lunar occultations.[11]

The spectroscopic binary nature of Xi1 Ceti was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory.[12][6] The pair have a circular orbit with a period of 4.5 years and a separation of 3.8 AU.[5] It is a suspected eclipsing binary with an amplitude of 0.03 in magnitude, which would suggest the orbital plane has a high inclination.[13]

The primary, designated component A, is a mild barium[14] giant star with a stellar classification of G7III Ba0.4 Fe-1.[3] Morgan and Keenan in 1973 had classified it as a bright giant star with an anomalous underabundance of the CN molecule.[15] Evidence has been found for an overabundance of s-process elements,[5] although this is disputed.[7] The star has 3.8[5] times the mass and 18[1] times the radius of the Sun. The companion, component B, is a small white dwarf companion with 80% of the mass of the Sun and a class of DA4.[4] It was detected in 1985 by its ultraviolet emission.[8]

In Chinese, 天囷 (Tiān Qūn), meaning Circular Celestial Granary, refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for Xi1 Ceti itself is "the Fifth Star of Circular Celestial Granary", Tiān Qūn Wu.[16]

References

  1. 1 2 3 4 5 6 7 8 9 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. 1 2 3 4 5 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.
  3. 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. 1 2 McCook, G. P.; Sion, E. M. (1999), "A Catalogue of Spectroscopically Identified White Dwarfs", The Astrophysical Journal Supplement Series, 121 (1): 1–130, Bibcode:1999ApJS..121....1M, doi:10.1086/313186.
  5. 1 2 3 4 5 6 7 8 Kong, X. M.; et al. (May 2018), "Chemical abundances of primary stars in the Sirius-like binary systems", Monthly Notices of the Royal Astronomical Society, 476 (1): 724–740, arXiv:1801.10284, Bibcode:2018MNRAS.476..724K, doi:10.1093/mnras/sty280.
  6. 1 2 Griffin, R. F.; Herbig, G. H. (1981). "Spectroscopic Orbits of Xi Piscium 60 Andromedae and ξ1 Ceti". Monthly Notices of the Royal Astronomical Society. 196: 33–43. Bibcode:1981MNRAS.196...33G. doi:10.1093/mnras/196.1.33.
  7. 1 2 Smiljanic, R.; et al. (June 2007), "Abundance analysis of barium and mild barium stars", Astronomy and Astrophysics, 468 (2): 679–693, arXiv:astro-ph/0702421, Bibcode:2007A&A...468..679S, doi:10.1051/0004-6361:20065867, S2CID 5863942.
  8. 1 2 Böhm-Vitense, E.; Johnson, H. R. (June 1985), "Detection of a compact companion of the mild barium star ksi1 Ceti", Astrophysical Journal, 293: 288–293, Bibcode:1985ApJ...293..288B, doi:10.1086/163236.
  9. ↑ "ksi01 Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-07-02.{{cite web}}: CS1 maint: postscript (link)
  10. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  11. ↑ Schmidtke, P. C.; Africano, J. L. (September 1984), "KPNO lunar occultation summary. I", Astronomical Journal, 89: 1371–1378, Bibcode:1984AJ.....89.1371S, doi:10.1086/113637.
  12. ↑ Campbell, William Wallace (1901). "Some recent results secured with the Mills spectrograph". Lick Observatory Bulletin. 1 (4): 22–25. Bibcode:1901LicOB...1...22C. doi:10.5479/ADS/bib/1901LicOB.1.22C.
  13. ↑ Hoffleit, Dorrit (1996), "A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars", The Journal of the American Association of Variable Star Observers, 24 (2): 105–116, Bibcode:1996JAVSO..24..105H.
  14. ↑ Pinsonneault, M. H.; et al. (March 1984), "Lithium in the barium stars", Publications of the Astronomical Society of the Pacific, 96: 239–246, Bibcode:1984PASP...96..239P, doi:10.1086/131327, S2CID 120248035.
  15. ↑ Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333.
  16. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
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