AR Aurigae

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AR Aurigae
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05h 18m 18.900s[1]
Declination +33° 46′ 02.45″[1]
Apparent magnitude (V) 6.144[2]
Spectral type B9V + B9.5V[3]
U−B color index −0.18[4]
B−V color index −0.06[4]
Variable type Algol[5]
Radial velocity (Rv)25.4 ± 0.9[6] km/s
Proper motion (μ) RA: 16.44 ± 0.47[1] mas/yr
Dec.: -29.23 ± 0.20[1] mas/yr
Parallax (π)8.19 ± 0.47[1] mas
Distance400 ± 20 ly
(122 ± 7 pc)
AR Aur A
Mass2.552 ± 0.008 M
Surface gravity (log g)4.33 cgs
Temperature10950 ± 150 K
AR Aur B
Mass2.367 ± 0.008 M
Surface gravity (log g)4.28 cgs
Temperature10350 ± 150 K
Other designations
17 Aur, BD+33° 1002, HD 34364, HIP 24740, HR 1728, SAO 57858, PPM 70158
Database references

AR Aurigae (AR Aur), also known by its Flamsteed designation 17 Aurigae, is an binary star in the constellation Auriga. Based on parallax measurements made by the Hipparcos spacecraft, it is approximately 400 light-years from Earth.[1]

Both components are blue-white B-type main-sequence stars that do not fill their Roche lobes. The system has a mean apparent magnitude of +6.15. However, the orbit of the stars are oriented in such a way that they periodically eclipse each other, so AR Aurigae is a variable star and its brightness varies from magnitude +6.15 to +6.82 with a period of 4.13 days.[5]

The primary component of AR Aurigae is known to be a mercury-manganese star, also known as an HgMn star. As the name implies, these stars have over-abundances of the elements mercury and manganese, and also often xenon and other elements.[3] Because AR Aurigae is an eclipsing binary (in fact, it is the only known eclipsing binary with a mercury-manganese star), accurate characterization of its parameters has been made possible. Based on the light-time effect observed from the stars, it is inferred that there is a third star with a mass of 0.54 M, orbiting at a separation of 13 au every 23.7 years.[3]


  1. ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. 
  3. ^ a b c d Folsom, C. P.; Kochukhov, O.; Wade, G. A.; Silvester, J.; Bagnulo, S. (2010). "Magnetic field, chemical composition and line profile variability of the peculiar eclipsing binary star AR Aur★". Monthly Notices of the Royal Astronomical Society. 407 (4): 2383. arXiv:1005.3793Freely accessible. Bibcode:2010MNRAS.407.2383F. doi:10.1111/j.1365-2966.2010.17057.x. 
  4. ^ a b Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Astronomy and Astrophysics Supplement Series. 34: 1–49. Bibcode:1978A&AS...34....1N. 
  5. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  6. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W. 

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