Xi1 Ceti

Xi¹ Ceti A

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cetus
Right ascension	02^h 12^m 59.995^s[1]
Declination	+08° 50′ 48.16″[1]
Apparent magnitude (V)	+4.37 [combined]
Characteristics
Spectral type	G, 6 or 8, III[2]
Astrometry
Proper motion (μ)	RA: –26.87 ± 0.48[1] mas/yr Dec.: –17.23 ± 0.36[1] mas/yr
Parallax (π)	8.51 ± 0.51[1] mas
Distance	380 ± 20 ly (118 ± 7 pc)
Absolute magnitude (MV)	–0.866[2]
Details
Mass	4[2] M☉
Radius	1.7[2] R☉
Luminosity	190[2] L☉
Temperature	4200[2] K
Age	300[2] Myr
Other designations
65 Ceti, HR 649, HD 13611, HIP 10324
Database references
SIMBAD	data
Exoplanet Archive	data

Xi¹ Ceti (ξ¹ Ceti), is a binary system located in the constellation Cetus, suspected as a ternary.

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, Xi¹ Ceti itself is known as the Fifth Star of Circular Celestial Granary, Tiān Qūn Wu.^[3]

The spectroscopic binary nature of Xi¹ Ceti was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory.^[4][5] The primary Ceti A is a G6III or G8III clump-giant star. The spectroscopic binary companion star is an A2V dwarf of about 2 solar masses and 30 luminosity. It is separated at 0.012 arcsec so in an orbit of 4.2 AU, smaller than the distance between Jupiter and the Sun.

Xi¹ Ceti A exhibits characteristics similar to an eclipsing binary, with a small white dwarf companion. Occultations with the moon have not yet confirmed the existence of the second suspected companion.

References

1. 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.Vizier catalog entry
2. Jim Kaler (Dec 21, 2007). "Xi-1 Ceti".
3. (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
4. 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.
5. 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.

• http://server3.wikisky.org/starview?object_type=1&object_id=979
• http://www.alcyone.de/cgi-bin/search.pl?object=HR0649