Pi Capricorni
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 20h 27m 19.21088s[1] |
| Declination | −18° 12′ 42.1980″[1] |
| Apparent magnitude (V) | +5.096[2] |
| Characteristics | |
| Spectral type | B8 II-III[3] or B4 V[4][5] |
| U−B color index | −0.311[2] |
| B−V color index | +0.013[2] |
| Astrometry | |
| Radial velocity (Rv) | −13[6] km/s |
| Proper motion (μ) | RA: +11.89[1] mas/yr Dec.: −11.35[1] mas/yr |
| Parallax (π) | 5.98 ± 0.58[1] mas |
| Distance | 550 ± 50 ly (170 ± 20 pc) |
| Details | |
| π Cap Aa | |
| Mass | 5.9±0.1[5] M☉ |
| Luminosity | 238[7] L☉ |
| Temperature | 9,623[7] K |
| Rotational velocity (v sin i) | 30[8] km/s |
| Age | 43.4±7.8[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi Capricorni (π Cap, π Capricorni) is a triple star in the southern constellation of Capricornus. It has the traditional star name Okul or Oculus (meaning eye in Latin).[10] The system is approximately 550 light years from Earth.
In Chinese, 牛宿 (Niú Su), meaning Ox (asterism), refers to an asterism consisting of π Capricorni, β Capricorni, α2 Capricorni, ξ2 Capricorni, ο Capricorni and ρ Capricorni.[11] Consequently, π Capricorni itself is known as 牛宿四 (Niú Su sì, English: the Fourth Star of Ox.)[12]
The primary member, component A, is a spectroscopic binary whose two components are separated by 0.1 arcseconds. The brighter of the two, component Aa, is a blue-white B-type bright giant or main sequence star with an apparent magnitude of +5.08. The third member, component B, is an eighth magnitude star 3.4 arcseconds from the primary.[13]
References
- 1 2 3 4 5 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 Rakos, K. D.; et al. (February 1982), "Photometric and astrometric observations of close visual binaries", Astronomy and Astrophysics Supplement Series, 47: 221–235, Bibcode:1982A&AS...47..221R.
- ↑ Cowley, A. (November 1972), "Spectral classification of the bright B8 stars", Astronomical Journal, 77: 750–755, Bibcode:1972AJ.....77..750C, doi:10.1086/111348.
- ↑ Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars, 4, Bibcode:1988MSS...C04....0H.
- 1 2 3 Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, Bibcode:2011MNRAS.410..190T, arXiv:1007.4883 , doi:10.1111/j.1365-2966.2010.17434.x.
- ↑ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- 1 2 McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427: 343, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
- ↑ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
- ↑ "pi. Cap -- Spectroscopic binary", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-12.
- ↑ Oculus, constellationsofwords, retrieved 2017-05-13.
- ↑ (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 5 月 13 日
- ↑ 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.
External links
- Kaler, James B. (November 7, 2014), "Pi Capricorni", Stars, University of Illinois, retrieved 2017-05-13.</ref>