45 Aurigae

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45 Aurigae
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension  06h 21m 46.12968s[1]
Declination +53° 27′ 07.8456″[1]
Apparent magnitude (V) 5.34[2]
Spectral type F5 V[3][2]
B−V color index 0.448±0.005[2]
Radial velocity (Rv)−0.4±0.1[4] km/s
Proper motion (μ) RA: +21.98[1] mas/yr
Dec.: -88.69[1] mas/yr
Parallax (π)16.89 ± 0.30[1] mas
Distance193 ± 3 ly
(59 ± 1 pc)
Absolute magnitude (MV)1.48[2]
Period (P)6.5011 d
Eccentricity (e)0.000
Periastron epoch (T)2444496.869 ± 0.006 JD
Argument of periastron (ω)
Semi-amplitude (K1)
32.0±0.2 km/s
45 Aur A
Mass1.20[6] M
Luminosity21.72[2] L
Surface gravity (log g)3.57±0.14[6] cgs
Temperature6,489±221[6] K
Metallicity [Fe/H]0.23±0.03[2] dex
Rotational velocity (v sin i)14[7] km/s
Age1.561[6] Gyr
Other designations
45 Aur, BD+53° 1008, FK5 2484, GC 8151, HD 43905, HIP 30247, HR 2264, SAO 25681, PPM 30377, PLX 1468.2, TYC 3764-2617-1[8]
Database references

45 Aurigae or PLX 1468.2 is a binary star[5] system in the northern constellation of Auriga. It has an apparent visual magnitude of 5.34,[2] making it visible to the naked eye under suitable viewing conditions. An annual parallax shift of 16.89 mas as seen from Earth's orbit indicates the system is located about 193 light years from the Sun.

This is a close, single-lined spectroscopic binary with a circularized orbit with a short period of 6.5 days.[5] They have a mean angular separation of 0.963 mas.[9] The visible component has a stellar classification of F5 V,[3] matching an F-type main-sequence star that is generating energy through hydrogen fusion at it core, it is about 1.6[6] billion years old and is spinning with a projected rotational velocity of 14 K.[7] It has 1.2[6] times the mass of the Sun and is radiating 22[2] times the Sun's luminosity from its photosphere at an effective temperature of around 6,489 K.[6] The secondary has a minimum mass of 42% of the Sun's mass.[9]


  1. ^ a b c d e 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.
  2. ^ a b c d e f g h 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 Abt, Helmut A. (January 2009), "MK Classifications of Spectroscopic Binaries", The Astrophysical Journal Supplement, 180 (1): 117–118, Bibcode:2009ApJS..180..117A, doi:10.1088/0067-0049/180/1/117.
  4. ^ 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.
  5. ^ a b c Mayor, M.; Mazeh, T. (January 1987), "The frequency of triple and multiple stellar systems", Astronomy and Astrophysics, 171: 157−177, Bibcode:1987A&A...171..157M.
  6. ^ a b c d e f g 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.
  7. ^ a b Böhm-Vitense, Erika (November 2004), "Rotation and Lithium Surface Abundances, Revisited", The Astronomical Journal, 128 (5): 2435−2442, Bibcode:2004AJ....128.2435B, doi:10.1086/425053.
  8. ^ "45 Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-07.
  9. ^ a b Tokovinin, A.; et al. (2008), Tertiary companions to close spectroscopic binaries, Berlin Heidelberg, p. 129, arXiv:astro-ph/0601518, Bibcode:2006yCat..34500681T.

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