12 Comae Berenices

Star in the constellation Coma Berenices Coma Berenices constellation map.svg center 260 right Red circle.svg 10 12 Comae Berenices 510 304 Location of 12 Comae Berenices (circled in red) J2000.0 Coma Berenices 12 22 30.31076 +25 50 46.1896 4.80 G7 III + A3 V 0.82/0.11 0.47/0.09 +0.5 0.9 −10.847 −9.546 11.8280 0.2353 0.55 0.06 / 1.05 0.06 396.4473 0.0002 days 0.599483 0.000026 64.8556 0.0011 46877.148 0.054 MJD 100.162 0.001 22.42 2.22 20.3358 0.00066 118.618 0.004 12 Com A 2.64 0.07 8.36 0.15 5300 200 commas 56.2 2.7 2.5 533 ± 41 ± 42 12 Com B 2.10 0.03 2.5 0.3 8500 500 commas 30.2 2.2 2.2 12 Com +26°2337 1318 107700 60351 4707 82273 J12225+2551A 5581 12+Com thumb|left|12 Comae Berenices in optical light 12 Comae Berenices is a binary star system in the northern constellation of Coma Berenices. It is the brightest member of the Coma Star Cluster and is visible to the naked eye with an apparent visual magnitude of 4.80. Although listed as a suspected variable star, there is no photometric evidence of it being variable in luminosity. However, the radial velocity was found to be variable, as announced by W. W. Campbell in 1910. The first orbital solution was published by Vinter Hansen in the 1940s. It is a double-lined spectroscopic binary with an orbital period of 396.5 days and an eccentricity of 0.566. This system consists of two stars, an evolved G-type giant star and a smaller but higher temperature A-type main-sequence star. Griffin and Griffin (2011) suggested that the secondary component may have begun its evolution away from the main sequence, and instead assigned it a luminosity class of IV. The primary, designated component A, has about 2.6 times the mass of the Sun and has expanded to 8.4 times the Sun's radius. It is radiating 56 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,300 K. Its companion, component B, has double the Sun's mass and 2.5 times the radius. It shines with 30 times the luminosity of the Sun at 8,500 K. References 12 Com December 30, 2018 4008342726516877312 Composite spectra: XVII. 12 Comae, a member of the Coma open cluster Griffin R. E. M. Griffin R. F. Astronomische Nachrichten 332 2 105–115 February 2011 10.1002/asna.201011514 2011AN....332..105G free Abt Helmut A. Visual Multiples. IX. MK Spectral Types The Astrophysical Journal Supplement Series 176 216–217 2008 1 2008ApJS..176..216A 10.1086/525529 free Mermilliod J. -C Andersen J. Latham D. W. Mayor M. Red giants in open clusters. XIII. Orbital elements of 156 spectroscopic binaries 1 Astronomy and Astrophysics 473 3 829 2007 2007A&A...473..829M 10.1051/0004-6361:20078007 free Evans D. S. June 20–24, 1966 Batten Alan Henry Heard John Frederick The Revision of the General Catalogue of Radial Velocities Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 30 57 University of Toronto International Astronomical Union 1967IAUS...30...57E 10.3847/1538-3881/accddb free Precise Age for the Binary Star System 12 Com in the Coma Berenices Cluster 2023 Lam Rex Sandquist Eric L. Schaefer Gail H. Farrington Christopher D. Monnier John D. Anugu Narsireddy Lanthermann Cyprien Klement Robert Ennis Jacob Setterholm Benjamin R. Gardner Tyler Kraus Stefan Davies Claire L. Orosz Jerome A. The Astronomical Journal 166 1 29 2304.07397 2023AJ....166...29L Category:Spectroscopic binaries Category:Coma Berenices Category:Durchmusterung objects Comae Berenices, 12 107700 060351 4707 Category:G7III stars Category:A3V stars