Astronomy:AR Aurigae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 18m 18.896s[2] |
| Declination | +33° 46′ 02.52″[2] |
| Apparent magnitude (V) | 6.144[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[4] |
| Spectral type | B9V + B9.5V[5] + M[6] |
| U−B color index | −0.18[7] |
| B−V color index | −0.06[7] |
| Variable type | Eclipsing[4] |
| Astrometry | |
| Radial velocity (Rv) | 28.65±0.09[8] km/s |
| Proper motion (μ) | RA: +15.254[2] mas/yr Dec.: −29.225[2] mas/yr |
| Parallax (π) | 7.0735 ± 0.0461[2] mas |
| Distance | 461 ± 3 ly (141.4 ± 0.9 pc) |
| Absolute magnitude (MV) | 1.11/1.17[9] |
| Orbit[4] | |
| Primary | AR Aur A |
| Companion | AR Aur B |
| Period (P) | 4.134581 days |
| Semi-major axis (a) | 0.08564±0.00018 astronomical unit|AU |
| Inclination (i) | 88.6000±0.0072° |
| Semi-amplitude (K1) (primary) | 108.36±0.18[8] km/s |
| Semi-amplitude (K2) (secondary) | 116.92±0.17[8] km/s |
| Orbit[6] | |
| Primary | AR Aur AB |
| Companion | AR Aur C |
| Period (P) | 23.365±0.090 years |
| Semi-major axis (a) | 14.351 ± 0.042 AU |
| Eccentricity (e) | 0.268±0.022 |
| Inclination (i) | 88.510° |
| Argument of periastron (ω) (secondary) | 13.4±4.6° |
| Details[4] | |
| AR Aur A | |
| Mass | 2.5444±0.0086 M☉ |
| Radius | 1.8433±0.0022 R☉ |
| Luminosity | 44.1+2.5 −2.4 L☉ |
| Surface gravity (log g) | 4.3125±0.0008 cgs |
| Temperature | 10,950±150[5] K |
| Rotational velocity (v sin i) | 22.555±0.027 km/s |
| Age | 33±3 Myr |
| AR Aur B | |
| Mass | 2.3581±0.0085 M☉ |
| Radius | 1.7658±0.0026 R☉ |
| Luminosity | 32.2+1.9 −1.8 L☉ |
| Surface gravity (log g) | 4.3169±0.0011 cgs |
| Temperature | 10,350±150[5] K |
| Rotational velocity (v sin i) | 21.604±0.032 km/s |
| Age | 33±3 Myr |
| AR Aur C | |
| Mass | 0.5122±0.0087[6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
AR Aurigae (AR Aur), also known by its Flamsteed designation 17 Aurigae, is a triple star in the constellation Auriga. Based on parallax measurements made by the Gaia spacecraft, it is approximately 461 light-years from Earth.[2]
Characteristics
The two inner components of this pair form an eclipsing binary system. This make AR Aurigae a variable star, with its brightness varying from magnitude +6.15 to +6.82 with a period of 4.13 days.[10] Both components are blue-white B-type main-sequence stars that do not fill their Roche lobes.[4]
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.[5] 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.
In 1931, H. N. Pendersen and J. C. Steensgard became the first persons to detect these eclipses.[11] When an eclipse is not occurring, the star will be faintly visible to the naked eye under very good observing conditions.
The third component has been detected by analysing the difference between the observed and the predicted time of eclipses, which is caused by the light-time effect of its orbital motion around the pair. This star has a mass of 0.54 M☉ and is orbiting at a separation of 13 AU every 23.7 years.[5]
References
- ↑ Johansen, K. T. (January 1970). "Light curve and photometric elements of AR Aurigae". Astronomy & Astrophysics 4: 1–10. Bibcode: 1970A&A.....4....1J.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Høg, E. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. Bibcode: 2000A&A...355L..27H.
- ↑ 4.0 4.1 4.2 4.3 4.4 Southworth, John (2025-07-29). "Rediscussion of eclipsing binaries. Paper XXV. The chemically-peculiar system AR Aurigae". arXiv:2507.21781 [astro-ph.EP].
- ↑ 5.0 5.1 5.2 5.3 5.4 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. doi:10.1111/j.1365-2966.2010.17057.x. Bibcode: 2010MNRAS.407.2383F.
- ↑ 6.0 6.1 6.2 Wilson, R. E.; Van Hamme, W. (2013-12-20). "Unification of Binary Star Ephemeris Solutions". The Astrophysical Journal 780 (2): 151. doi:10.1088/0004-637x/780/2/151. ISSN 0004-637X.
- ↑ 7.0 7.1 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.
- ↑ 8.0 8.1 8.2 Hubrig, S.; González, J. F.; Ilyin, I.; Korhonen, H.; Schöller, M.; Savanov, I.; Arlt, R.; Castelli, F. et al. (2012-11-01). "Magnetic fields of HgMn stars" (in en). Astronomy & Astrophysics 547: A90. doi:10.1051/0004-6361/201219778. ISSN 0004-6361. Bibcode: 2012A&A...547A..90H.
- ↑ Nordstrom, B.; Johansen, K. T. (1994). "Radii and masses for the young star AR Aurigae". Astronomy and Astrophysics 282: 787. Bibcode: 1994A&A...282..787N.
- ↑ Samus, N. N. 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.
- ↑ Nassau, J. J. (July 1936). "Light elements and orbit of AR Aurigae". Astronomical Journal 45 (1051): 137–140. doi:10.1086/105358. Bibcode: 1936AJ.....45..137N. https://articles.adsabs.harvard.edu/pdf/1936AJ.....45..137N. Retrieved 29 November 2024.
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