Mu Aurigae

Mu Aurigae, Latinized as μ Aurigae, is the Bayer designation for an unconfirmed binary star[12] in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of +4.88.[2] Based upon an annual parallax shift of 20.7218±0.4971 mas as seen from Earth,[7] is located 157 light years from the Sun.

Mu Aurigae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Auriga
Right ascension 05h 13m 25.71733s[1]
Declination +38° 29′ 04.1879″[1]
Apparent magnitude (V) +4.88[2]
Characteristics
Spectral type A4 Vm[3][4] (kA3hA8VmA8[5])
U−B color index +0.10[2]
B−V color index +0.18[2]
Astrometry
Radial velocity (Rv)+26.0±1.2[6] km/s
Proper motion (μ) RA: −19.545[7] mas/yr
Dec.: −72.456[7] mas/yr
Parallax (π)20.7218 ± 0.4971[7] mas
Distance157 ± 4 ly
(48 ± 1 pc)
Absolute magnitude (MV)+1.47[8]
Details
Mass2.09[9] M☉
Radius3.15[7] R☉
Luminosity22.95[7] L☉
Surface gravity (log g)3.4[10] cgs
Temperature7,500[10] K
Metallicity [Fe/H]−0.3[10] dex
Rotational velocity (v sin i)80.0[10] km/s
Age560[9] Myr
Other designations
μ Ari, 11 Aurigae, BD+38°1063, FK5 192, HD 33641, HIP 24340, HR 1689, SAO 57755, WDS J05134+3829AB[11]
Database references
SIMBADdata

This is an A-type main sequence star with a stellar classification of A4 Vm;[4] the 'm' suffix indicating that abnormal abundances of heavier elements appear in the star's spectrum, making this an Am star. It is 560[9] million years old with a projected rotational velocity of 80 km/s.[10] It has double[9] the mass of the Sun and is radiating 23[7] times the Sun's luminosity at an effective temperature of 7,500 K.[10]

A very close companion has been reported using speckle interferometry,[12] but this remains unconfirmed. The separation at discovery in 1986 was 0.07 mas and it was measured at 0.066 mas in 1999. It was catalogued by Hipparcos as a problem binary, indicating that the measurements of its position were not consistent with the motion of a single star, but no satisfactory orbit could be found to match the motion[12]

Name

This star, along with λ Aur and ρ Aur, were Kazwini's Al Ḣibāʽ (ألحباع), the Tent.[13] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Ḣibāʽ were the title for three stars : λ Aur as Al Ḣibāʽ I, μ Aur as Al Ḣibāʽ II and σ Aur as Al Ḣibāʽ III.[14]

In Chinese, 天潢 (Tiān Guāng), meaning Celestial Pier, refers to an asterism consisting of μ Aurigae, 19 Aurigae, φ Aurigae, 14 Aurigae and σ Aurigae.[15] Consequently, μ Aurigae itself is known as 天潢五 (Tiān Guāng wu, English: the First Star of Celestial Pier.)[16]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763.
  4. 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  5. Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  6. 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  7. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  9. De Rosa, R. J.; et al. (January 2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216–1240, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932, S2CID 88503488.
  10. Gebran, M.; Farah, W.; Paletou, F.; Monier, R.; Watson, V. (2016), "A new method for the inversion of atmospheric parameters of A/Am stars", Astronomy and Astrophysics, 589: A83, arXiv:1603.01146, Bibcode:2016A&A...589A..83G, doi:10.1051/0004-6361/201528052, S2CID 118549566.
  11. "ksi Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-28.
  12. Mason, Brian D.; Martin, Christian; Hartkopf, William I.; Barry, Donald J.; Germain, Marvin E.; Douglass, Geoffrey G.; Worley, Charles E.; Wycoff, Gary L.; Ten Brummelaar, Theo; Franz, Otto G. (1999), "Speckle Interferometry of New and Problem HIPPARCOS Binaries", The Astronomical Journal, 117 (4): 1890, Bibcode:1999AJ....117.1890M, doi:10.1086/300823.
  13. Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 91, ISBN 0-486-21079-0, retrieved 2010-12-12.
  14. Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
  15. (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.
  16. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 13 日
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