Pi Ceti

Pi Ceti, Latinized from π Ceti, is the Bayer designation for a star system in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 4.238.[2] Based upon an annual parallax shift of 8.30 mas,[1] it is located around 393 light years from the Sun.

Pi Ceti

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Cetus
Right ascension	02^h 44^m 07.34928^s[1]
Declination	−13° 51′ 31.3130″[1]
Apparent magnitude (V)	4.238[2]
Characteristics
Spectral type	B7 V[3] or B7 IV[4]
U−B color index	−0.396[2]
B−V color index	−0.130[2]
Astrometry
Proper motion (μ)	RA: −8.62[1] mas/yr Dec.: −9.07[1] mas/yr
Parallax (π)	8.30 ± 0.21[1] mas
Distance	393 ± 10 ly (120 ± 3 pc)
Absolute magnitude (MV)	−1.16[5]
Orbit[6]
Period (P)	2,722±14 d
Eccentricity (e)	0.0±0.7
Periastron epoch (T)	2444852 ± 29 JD
Argument of periastron (ω) (secondary)	0.0°
Semi-amplitude (K1) (primary)	4.33±0.25 km/s
Details[7]
π Cet A
Mass	4.4±0.2 M☉
Radius	4.3±0.3 R☉
Luminosity	468 L☉
Surface gravity (log g)	3.8±0.2 cgs
Temperature	12,900±400 K
Metallicity [Fe/H]	0.28±0.16[8] dex
Rotational velocity (v sin i)	20.9±1.2 km/s
Age	0.3+0.1 −0.1 Myr
Other designations
π Cet, 89 Ceti, BD−14 519, FK5 97, HD 17081, HIP 12770, HR 811, SAO 148575.[9]
Database references
SIMBAD	data

This is a single-lined spectroscopic binary system with a nearly circular orbit and a period of 7.45 years. The fact that the system has a negligible eccentricity is surprising for such a long period, and may suggest that the secondary is a white dwarf that had its orbit circularized during a mass-transfer event.[6]

The primary, component A, is a normal B-type star[7] that has been given stellar classifications of B7 V[3] and B7 IV.[4] It appears very young – less than half a million years in age – and may still be on a pre-main sequence track. The star shows no magnetic field but it does emit an infrared excess.[7]

Name

This star, along with ε Cet, ρ Cet and σ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast [10]

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Sadr al Ḳaiṭos were the title for four stars :ρ Cet as Al Sadr al Ḳaiṭos I, σ Cet as Al Sadr al Ḳaiṭos II, ε Cet as Al Sadr al Ḳaiṭos III and π Cet as Al Sadr al Ḳaiṭos IV[11]

In Chinese, 天苑 (Tiān Yuàn), meaning Celestial Meadows, refers to an asterism consisting of π Ceti, γ Eridani, π Eridani, δ Eridani, ε Eridani, ζ Eridani, η Eridani, τ¹ Eridani, τ² Eridani, τ³ Eridani, τ⁴ Eridani, τ⁵ Eridani, τ⁶ Eridani, τ⁷ Eridani, τ⁸ Eridani and τ⁹ Eridani. Consequently, the Chinese name for δ Ceti itself is 天苑七 (Tiān Yuàn qī, English: the Seventh Star of Celestial Meadows.)[12]

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.
2. Gutierrez-Moreno, Adelina; et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G.
3. Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram, 4, Bibcode:1962MtSOM...4....1B.
4. Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355.
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.
6. Lacy, C. H. S.; et al. (March 1997), "The Spectroscopic Orbit of Pi Ceti", Astronomical Journal, 113: 1088, Bibcode:1997AJ....113.1088L, doi:10.1086/118325.
7. Folsom, C. P.; et al. (May 2012), "Chemical abundances of magnetic and non-magnetic Herbig Ae/Be stars", Monthly Notices of the Royal Astronomical Society, 422 (3): 2072–2101, arXiv:1202.1845, Bibcode:2012MNRAS.422.2072F, doi:10.1111/j.1365-2966.2012.20718.x.
8. Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769.
9. "pi. Cet -- Spectroscopic binary", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-02-08.
10. Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 162. ISBN 0-486-21079-0. Retrieved 2010-12-12.
11. Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
12. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 12 日