42 Aurigae

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42 Aurigae
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension  06h 17m 34.6465s[1]
Declination +46° 25′ 26.230″[1]
Apparent magnitude (V) 6.53[2]
Spectral type F0 V[3] or A6 Vp(4481 wk)n[4]
B−V color index 0.263±0.003[2]
Radial velocity (Rv)−12.0±1.0[5] km/s
Proper motion (μ) RA: −43.520[1] mas/yr
Dec.: +11.147[1] mas/yr
Parallax (π)13.24 ± 0.38[1] mas
Distance246 ± 7 ly
(76 ± 2 pc)
Absolute magnitude (MV)2.27[2]
Mass1.70±0.02[6] M
Luminosity10.29[2] L
Surface gravity (log g)4.18±0.14[7] cgs
Temperature7,660±260[7] K
Rotational velocity (v sin i)228[6] km/s
Age1.042[7] Gyr
Other designations
42 Aur, BD+46° 1122, HD 43244, HIP 29884, HR 2228, SAO 40999[8]
Database references

42 Aurigae is a star in the northern constellation of Auriga. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712, it has an apparent visual magnitude of 6.53,[2] which places it just below the visibility limit for normal eyesight under good seeing conditions. It displays an annual parallax shift of 13.24 mas, which yields a distance estimate of around 246 light years. The star is moving closer to the Sun with a radial velocity of −12 km/s,[5] it is a member of the Ursa Major Moving Group of stars that share a common motion through space.[9]

The star was assigned a stellar classification of F0 V by Nancy Roman in 1949,[3] indicating it is an F-type main-sequence star. However, in 1995 Abt and Morrell catalogued it as class A6 Vp(4481 wk)n;[4] a somewhat hotter and more massive A-type main-sequence star that displays spectral peculiarities as well as nebulous lines brought about by rapid rotation. It is around a billion years old[7] with a high rate of spin, showing a projected rotational velocity of 228 km/s;[6] the star has an estimated 1.7[6] times the mass of the Sun and is radiating 10[2] times the Sun's luminosity from its photosphere at an effective temperature of around 7,660 K.[7]


  1. ^ a b c d e Gaia Collaboration; et al. (November 2016), "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties", Astronomy & Astrophysics, 595: 23, arXiv:1609.04172, Bibcode:2016A&A...595A...2G, doi:10.1051/0004-6361/201629512, A2.
  2. ^ a b c d e f 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.
  3. ^ a b Roman, Nancy Grace (September 1949), "The Ursa Major Group", Astrophysical Journal, 110: 205, Bibcode:1949ApJ...110..205R, doi:10.1086/145199.
  4. ^ a b Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
  5. ^ a b 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, A61.
  6. ^ a b c d Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, A120.
  7. ^ a b c d e David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  8. ^ "42 Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-07.
  9. ^ Chupina, N. V.; et al. (June 2006), "Kinematic structure of the corona of the Ursa Major flow found using proper motions and radial velocities of single stars", Astronomy and Astrophysics, 451 (3): 909–916, Bibcode:2006A&A...451..909C, doi:10.1051/0004-6361:20054009.