Pi Ceti
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 44m 07.34928s[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) |
| Orbit[5] | |
| 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[6] | |
| 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[7] dex |
| Rotational velocity (v sin i) | 20.9±1.2 km/s |
| Age | 0.3+0.1 −0.1 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi Ceti (π Ceti, π Cet) 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.
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.[5]
The primary, component A, is a normal B-type star[6] 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.[6]
Name
This star, along with ε Cet, ρ Cet and σ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast [9]
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[10]
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.[11] Consequently, δ Ceti itself is known as 天苑七 (Tiān Yuàn qī, English: the Seventh Star of Celestial Meadows.)[12]
References
- 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752
, doi:10.1051/0004-6361:20078357. - 1 2 3 4 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.
- 1 2 Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram, 4, Bibcode:1962MtSOM...4....1B.
- 1 2 Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, Bibcode:2010AN....331..349H, arXiv:1003.2335 , doi:10.1002/asna.200911355.
- 1 2 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.
- 1 2 3 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, Bibcode:2012MNRAS.422.2072F, arXiv:1202.1845 , doi:10.1111/j.1365-2966.2012.20718.x.
- ↑ Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, Bibcode:2011A&A...531A.165P, arXiv:1104.4952 , doi:10.1051/0004-6361/201116769.
- ↑ "pi. Cet -- Spectroscopic binary", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-02-08.
- ↑ 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.
- ↑ 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
- ↑ (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.
- ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 12 日