Astronomy:Theta Cancri
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| Observation data 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 | |
| Evolutionary stage | red giant branch[2] |
| 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[2] mas/yr Dec.: −56.615[2] mas/yr |
| Parallax (π) | 7.5577 ± 0.1008[2] mas |
| Distance | 432 ± 6 ly (132 ± 2 pc) |
| Absolute magnitude (MV) | −0.19[1] |
| Details | |
| Mass | 1.3[6] M☉ |
| Radius | 67[2] R☉ |
| Luminosity | 949[2] L☉ |
| Surface gravity (log g) | 1.82[6] cgs |
| Temperature | 3,998[6] K |
| Metallicity [Fe/H] | −0.19[6] dex |
| Other designations | |
| 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 67 times the girth of the Sun. It is radiating 949[2] times the luminosity of the Sun at an effective temperature of 3,998 K.[6]
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
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940. Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 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.
- ↑ 4.0 4.1 4.2 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.
- ↑ 5.0 5.1 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.
- ↑ 6.0 6.1 6.2 6.3 6.4 Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G. et al. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics 691: A98. doi:10.1051/0004-6361/202451427. Bibcode: 2024A&A...691A..98K.
- ↑ "tet Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tet+Cnc.
- ↑ 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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