This star has two Bayer designations: β Tauri (Latinised to Beta Tauri) and γ Aurigae (Latinised to Gamma Aurigae). Ptolemy considered the star to be shared by Auriga, and Johann Bayer assigned it a designation in both constellations. When the modern constellation boundaries were fixed in 1930, the designation γ Aurigae largely dropped from use.
The traditional name Elnath, variously El Nath or Alnath, comes from the Arabic word النطحan-naţħ, meaning "the butting" (i.e. the bull's horns). As in many other Arabic star names, the article ال is transliterated literally as el, yet overwhelmingly in Arabic pronunciation it is assimilated to the n, meaning it is omitted. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Elnath for this star.
The absolute magnitude of Beta Tauri is −1.34, similar to another star in Taurus, Maia in the Pleiadesstar cluster. Like Maia, β Tauri is a B-classgiant with a luminosity 700 times solar (L☉). It has evolved to become a giant star, larger and cooler than when it was on the main sequence.
However, being approximately 130 light-years distant compared to Maia's estimated 360 light-years, β Tauri ranks as the second-brightest star in the constellation.
It is a mercury-manganese star, a type of non-magnetic chemically peculiar star with unusually large signatures of some heavy elements in its spectrum. Relative to the Sun, β Tauri is notable for a high abundance of manganese, but little calcium and magnesium. However, the lack of strong mercury signatures, together with notably high levels of silicon and chromium, have led some authors to give other classifications, including as a "SrCrEu star" or even an Ap star. Its limb-darkened angular diameter has been measured at 1.090±0.076 mas. At a distance of 41.1 pc, this corresponds to a linear radius of 4.82±0.34 R☉.
A faint star is, angularly from our viewpoint, close enough for astronomers to consider, and guides to mention, the pair a double star. This visual companion, BD+28°795B, has a position angle of 239 degrees and is separated from the main star by 33.4 arcseconds (″). Six angularly closer, even fainter stars have been found in a search for brown dwarf and planetary companions – all considered background objects.
^Garrison, R. F; Gray, R. O (1994). "The late B-type stars: Refined MK classification, confrontation with stromgren photometry, and the effects of rotation". The Astronomical Journal. 107: 1556. Bibcode:1994AJ....107.1556G. doi:10.1086/116967.
^Evans, D. S (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications. 30: 57. Bibcode:1967IAUS...30...57E.
^ abJanson, Markus; et al. (August 2011). "High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood". The Astrophysical Journal. 736 (2): 89. arXiv:1105.2577. Bibcode:2011ApJ...736...89J. doi:10.1088/0004-637X/736/2/89. S2CID 119217803.
^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. ISBN 978-1-931559-44-7.
^Ian Ridpath. "Bayer's Uranometria and Bayer letters". Retrieved 2017-11-27.
^"IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
^"Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
^(in Chinese)中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
^(in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
^Knyazeva, L. N; Kharitonov, A. V (2000). "The Normal Energy Distributions in Stellar Spectra: Giants and Supergiants". Astronomy Reports. 44 (8): 548. Bibcode:2000ARep...44..548K. doi:10.1134/1.1306355. S2CID 120800469.
^Chen, P. S; Liu, J. Y; Shan, H. G (2017). "A New Photometric Study of Ap and Am Stars in the Infrared". The Astronomical Journal. 153 (5): 218. Bibcode:2017AJ....153..218C. doi:10.3847/1538-3881/aa679a.
^"Al Nath". Alcyone Bright Star Catalogue. Retrieved 2010-03-07.
^Janson, Markus; Bonavita, Mariangela; Klahr, Hubert; Lafrenière, David; Jayawardhana, Ray; Zinnecker, Hans (2011). "High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood". The Astrophysical Journal. 736 (2): 89. arXiv:1105.2577. Bibcode:2011ApJ...736...89J. doi:10.1088/0004-637X/736/2/89. S2CID 119217803.
^Adelman, S. J.; Caliskan, H.; Gulliver, A. F.; Teker, A. (2006). "Elemental abundance analyses with DAO spectrograms". Astronomy & Astrophysics. 447 (2): 685–690. doi:10.1051/0004-6361:20053581.
Jim Kaler's Stars: Elnath
NASA Astronomy Picture of the Day: Image of Elnath (5 March 2010)