Theta Cancri
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cancer[1] |
| Right ascension | 08h 31m 35.730s[2] |
| Declination | +18° 05′ 39.91″[2] |
| Apparent magnitude (V) | +5.323[3] |
| Characteristics | |
| Spectral type | K5 III[4] |
| U−B color index | +1.949[3] |
| B−V color index | +1.565[3] |
| Astrometry | |
| Radial velocity (Rv) | +44.47±0.19[5] km/s |
| Proper motion (μ) | RA: −59.639 mas/yr[2] Dec.: −56.615 mas/yr[2] |
| Parallax (π) | 7.5577±0.1008 mas[2] |
| Distance | 432 ± 6 ly (132 ± 2 pc) |
| Absolute magnitude (MV) | −0.19[1] |
| Details | |
| Radius | 40.02+2.22 −2.35[6] R☉ |
| Luminosity | 353.1±10.1[6] L☉ |
| Surface gravity (log g) | 4.41+0.79 −0.24[2] cgs |
| Temperature | 4,600+4 −11[2] K |
| Other designations | |
| θ Cnc, 31 Cancri, BD+18°1963, FK5 2667, HD 72094, HIP 41822, HR 3357, SAO 97881[7] | |
| Database references | |
| SIMBAD | data |
Theta Cancri, is a multiple star[8][4] system in the zodiac constellation of Cancer. Its name is a Bayer designation that is Latinised from θ Cancri, and abbreviated Theta Cnc or θ Cnc. This star is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.32.[3] The system is located at a distance of approximately 432 light-years (132 pc) from the Sun, based on parallax,[2] and is drifting further away with a radial velocity of +44 km/s.[5] Since it is near the ecliptic, it can be occulted by the Moon[9] and, very rarely, by planets.
The primary, designated component A, is K-type giant star with a stellar classification of K5 III,[4] having exhausted the supply of hydrogen at its core, then cooled and expanded. At present it has 40[6] times the girth of the Sun. It is radiating 353[6] times the luminosity of the Sun at an effective temperature of 4,600 K.[2]
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.[10] 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.[11]
References
[edit]- ^ a b 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. XHIP record for this object at VizieR.
- ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
- ^ a b c 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ a b 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (August 2018), "Gaia Data Release 2: Summary of the contents and survey properties", Astronomy & Astrophysics, 616, A1, arXiv:1804.09365, Bibcode:2018A&A...616A...1G, doi:10.1051/0004-6361/201833051 Gaia DR2 record for this source at VizieR.
- ^ "tet Cnc", SIMBAD, Centre de données astronomiques de Strasbourg, 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, Bibcode:1984PASP...96..105H, doi:10.1086/131309.
- ^ White, Nathaniel M.; Feierman, Barry H. (September 1987), "A Catalog of Stellar Angular Diameters Measured by Lunar Occultation", Astronomical Journal, 94: 751, Bibcode:1987AJ.....94..751W, doi:10.1086/114513.
- ^ 陳久金 (2005), Zhōngguó Xīngzuò Shénhuà 中國星座神話 [Chinese Constellation Mythology], 台灣古籍出版有限公司, p. 394, ISBN 978-986-7332-25-7.
- ^ 陳久金 (2005), Zhōngguó Xīngzuò Shénhuà 中國星座神話 [Chinese Constellation Mythology], 台灣古籍出版有限公司, p. 193, ISBN 978-986-7332-25-7.
