Astronomy:Theta Cancri
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 31m 35.73082s[1] |
| Declination | +18° 05′ 39.9166″[1] |
| Apparent magnitude (V) | +5.323[2] |
| Characteristics | |
| Spectral type | K5 III[3] |
| U−B color index | +1.949[2] |
| B−V color index | +1.565[2] |
| Astrometry | |
| Radial velocity (Rv) | +44.47±0.19[4] km/s |
| Proper motion (μ) | RA: −60.438[1] mas/yr Dec.: −57.331[1] mas/yr |
| Parallax (π) | 7.3204 ± 0.1826[1] mas |
| Distance | 450 ± 10 ly (137 ± 3 pc) |
| Absolute magnitude (MV) | −0.19[5] |
| Details | |
| Radius | 40.02+2.22 −2.35[1] R☉ |
| Luminosity | 353.1±10.1[1] L☉ |
| Temperature | 3,955+121 −105[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Cancri, Latinised from θ Cancri, is a multiple star[7][3] system in the zodiac constellation of Cancer. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.32.[2] The system is located at a distance of approximately 450 light-years away from the Sun, based on parallax,[1] and is drifting further away with a radial velocity of +44 km/s.[4] Since it is near the ecliptic, it can be occulted by the Moon[8] and, very rarely, by planets.
The primary, designated component A, is K-type giant star with a stellar classification of K5 III,[3] having exhausted the supply of hydrogen at its core, then cooled and expanded. At present it has 40[1] times the girth of the Sun. It is radiating 353[1] times the luminosity of the Sun at an effective temperature of 3,955 K.[1]
In Chinese astronomy, Ghost (Chinese: 鬼宿; pinyin: Guǐ Xiù) refers to an asterism consisting of Theta Cancri, Eta Cancri, Gamma Cancri and Delta Cancri.[9] Theta Cancri is the first star of Ghost (Chinese: 鬼宿一; pinyin: Guǐ Xiù yī), as it is also the determinative star for that asterism.[10]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Gutierrez-Moreno, Adelina et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile (Publicaciones Universidad de Chile, Department de Astronomy) 1: 1–17, Bibcode: 1966PDAUC...1....1G.
- ↑ 3.0 3.1 3.2 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 4.0 4.1 de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ "tet Cnc -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=tet+Cnc, retrieved 2017-06-19.
- ↑ Hartkopf, W. I.; McAlister, H. A. (January 1984), "Binary stars unresolved by speckle interferometry. III", Publications of the Astronomical Society of the Pacific 96: 105–116, doi:10.1086/131309, Bibcode: 1984PASP...96..105H.
- ↑ White, Nathaniel M.; Feierman, Barry H. (September 1987), "A Catalog of Stellar Angular Diameters Measured by Lunar Occultation", Astronomical Journal 94: 751, doi:10.1086/114513, Bibcode: 1987AJ.....94..751W.
- ↑ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà. 台灣古籍出版有限公司. p. 394. ISBN 978-986-7332-25-7. https://books.google.com/books?id=0Vex0rYzdu8C&pg=394.
- ↑ 陳久金 (2005). Zhōngguó Xīngzuò Shénhuà. 台灣古籍出版有限公司. p. 193. ISBN 978-986-7332-25-7. https://books.google.com/books?id=0Vex0rYzdu8C&pg=193.
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