Beta Comae Berenices (β Comae Berenices, β Com) is a main sequence dwarf star in the northern constellation of Coma Berenices. It is located at a distance of about 29.95 light-years (9.18 parsecs) from Earth. The Greek letter beta (β) usually indicates that the star has the second highest visual magnitude in the constellation. However, with an apparent visual magnitude of 4.3,[2] this star is actually slightly brighter than α Comae Berenices. It can be seen with the naked eye, but may be too dim to be viewed from a built-up urban area.
The star is similar to the Sun, being only slightly larger and brighter in absolute magnitude. It has a stellar classification of G0V,[3] compared to G2V for the Sun. The effective temperature of the outer envelope is 5,936K,[9] giving it a yellow hue of a G-type star.[13] In terms of age it is younger than the Sun, being about 3 billion years old.[11]
Observations of short term variations in the chromatic activity suggest that the star undergoes differential rotation,[14] with a rotation period of about 11–13 days.[10] Its surface has a measured activity cycle of 16.6 years, compared to 11 years on the Sun. It may also have a secondary activity cycle of 9.6 years.[15] At one time it was thought that this star might have a spectroscopic companion. However, this was ruled out by means of more accurate radial velocity measurements. No planets have yet been detected around it, and there is no evidence of a dusty disk.
The habitable zone for this star, defined as the locations where liquid water could be present on an Earth-like planet, is 0.918–1.96AU, where 1 AU is the average distance from the Earth to the Sun.[16]
Johnson, H. L.; etal. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956
Mallik, Sushma V. (October 1998). "Chromospheric activity in cool stars and the lithium abundance". Astronomy and Astrophysics. 338: 623–636. Bibcode:1998A&A...338..623M.
Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
Holmberg, J.; etal. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID118577511.
Takeda, G.; etal. (2007). "Stellar parameters of nearby cool stars. II. Physical properties of ~1000 cool stars from the SPOCS catalog". Astrophysical Journal Supplement Series. 168 (2): 297–318. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763. S2CID18775378. Note: see VizieR catalogue J/ApJS/168/297.
Boyajian, Tabetha S.; etal. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID18993744. See Table 10.
Gray, David F.; Baliunas, Sallie L. (January 1997), "The Rotation of the G0 Dwarf beta Comae", Astrophysical Journal, 475 (1): 303–312, Bibcode:1997ApJ...475..303G, doi:10.1086/303522
Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785. S2CID27151456.
"The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
Donahue, Robert A.; Baliunas, Sallie L. (July 1992), "Evidence of differential surface rotation in the solar-type star HD 114710", Astrophysical Journal Letters, 393 (2): L63–L66, Bibcode:1992ApJ...393L..63D, doi:10.1086/186452
Baliunas, S. L.; etal. (January 1995), "Chromospheric variations in main-sequence stars", Astrophysical Journal, Part 1, 438 (1): 269–287, Bibcode:1995ApJ...438..269B, doi:10.1086/175072 See appendix A.
Cantrell, Justin R.; etal. (October 2013), "The Solar Neighborhood XXIX: The Habitable Real Estate of Our Nearest Stellar Neighbors", The Astronomical Journal, 146 (4): 99, arXiv:1307.7038, Bibcode:2013AJ....146...99C, doi:10.1088/0004-6256/146/4/99, S2CID44208180
Другой контент может иметь иную лицензию. Перед использованием материалов сайта WikiSort.org внимательно изучите правила лицензирования конкретных элементов наполнения сайта.
2019-2025 WikiSort.org - проект по пересортировке и дополнению контента Википедии