Mu Geminorum forms the primary or 'A' component of a double star system designated WDS J06230+2231 along with UCAC2 39641417[15] (also designated WDS J06230+2231BC), itself a binary pair.[16]
Nomenclature
[edit]μ Gem is the star on the left, surrounded by the S249 nebula. The bright star on the right, near the IC 443 supernova remnant, is η Gem.
Mu Geminorum bore the traditional name of Tejat (or more precisely, Tejat Posterior), from an old southern Arabic word of unknown meaning, tiḥyāt.[18] The name Tejat Posterior was formerly applied to an asterism consisting of this star, along with Gamma Geminorum (Alhena), Nu Geminorum, Eta Geminorum (Propus), and Xi Geminorum (Alzirr).[16] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[19] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[20] It approved the name Tejat for the component WDS J06230+2231A (i.e. Mu Geminorum) on February 1, 2017 and it is now so included in the List of IAU-approved Star Names.[13]
The names Calx (Latin, meaning 'heel'), Pish Pai (from the Persian پیشپای ('pīshpāy', meaning 'foreleg'), and Nuhatai (from Arabic 'Al Nuḥātai', the dual form of 'Al Nuḥāt', 'a Camel's Hump') have also been applied to Mu Geminorum.[21]
It is a slow irregular variable of type LB. Its brightness varies between magnitude +2.75 and +3.02 over a 72-day period, along with a 2,000-day period of long term variation. It is a red giant at a stellar classification of M3 III,[4] with a surface temperature of 3,773 K,[26] meaning it is brighter, yet cooler, than the Sun.[2][16] The star is currently on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.[3]
^ abcGutierrez-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.
^Schiavon, Ricardo P. (July 2007), "Population Synthesis in the Blue. IV. Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations", The Astrophysical Journal Supplement Series, 171 (1): 146–205, arXiv:astro-ph/0611464, Bibcode:2007ApJS..171..146S, doi:10.1086/511753, S2CID13946698.
^ abcTejat, Jim Kaler's STARS, retrieved 2017-03-31.
^Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010), On the naming convention used for multiple star systems and extrasolar planets, arXiv:1012.0707.
^Kunitzsch, Paul; Smart, Tim (2006), A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.), Cambridge, Massachusetts: Sky Pub, ISBN978-1-931559-44-7.
^Percy, John R.; Wilson, Joseph B.; Henry, Gregory W. (August 2001), "Long-Term VRI Photometry of Small-Amplitude Red Variables. I. Light Curves and Periods", Publications of the Astronomical Society of the Pacific, 113 (786): 983–996, Bibcode:2000AAS...197.4614P, doi:10.1086/322153, JSTOR10.1086/322153, S2CID14609175.
^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.
^Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M.
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