AR Aurigae (AR Aur), also known by its Flamsteed designation 17 Aurigae, is a binary star in the constellation Auriga. Based on parallax measurements made by the Hipparcos spacecraft, it is approximately 461 light-years from Earth.[10]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Auriga |
Right ascension | 05h 18m 18.896s[2] |
Declination | +33° 46′ 02.52″[2] |
Apparent magnitude (V) | 6.144[3] |
Characteristics | |
Spectral type | B9V + B9.5V[4] |
U−B color index | −0.18[5] |
B−V color index | −0.06[5] |
Variable type | Algol[6] |
Astrometry | |
Radial velocity (Rv) | 25.4±0.9[7] km/s |
Proper motion (μ) | RA: +15.254[2] mas/yr Dec.: −29.225[2] mas/yr |
Parallax (π) | 7.0735 ± 0.0461 mas[2] |
Distance | 461 ± 3 ly (141.4 ± 0.9 pc) |
Absolute magnitude (MV) | 1.11/1.17[8] |
Details | |
AR Aur A | |
Mass | 2.552±0.008[4] M☉ |
Radius | 1.781[9] R☉ |
Luminosity | 41[8] L☉ |
Surface gravity (log g) | 4.33[4] cgs |
Temperature | 10,950±150[4] K |
Rotational velocity (v sin i) | 10[9] km/s |
AR Aur B | |
Mass | 2.367±0.008[4] M☉ |
Radius | 1.816[9] R☉ |
Luminosity | 34[8] L☉ |
Surface gravity (log g) | 4.28[4] cgs |
Temperature | 10,350±150[4] K |
Rotational velocity (v sin i) | 11[9] km/s |
Other designations | |
Database references | |
SIMBAD | data |
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.[6]
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.[4] 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.[4]