R Aurigae

Not to be confused with Rho Aurigae.

R Aurigae (R Aur) is a Mira variable, a pulsating red giant star in the constellation of Auriga, at a distance of 930 light years.

R Aurigae

The visual band light curve of R Aurigae, from AAVSO data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Auriga
Right ascension	05h 17m 17.6916s[2]
Declination	+53° 35′ 10.032″[2]
Apparent magnitude (V)	6.7 to 13.9[3]
Characteristics
Spectral type	M7IIIe[4] (M6e - M9e)[3]
U−B color index	+0.27[5]
B−V color index	+1.66[5]
Variable type	Mira[3]
Astrometry
Radial velocity (Rv)	7.8 ± 2[6] km/s
Proper motion (μ)	RA: 14.708[2] mas/yr Dec.: −14.685[2] mas/yr
Parallax (π)	3.4958±0.1327 mas[2]
Distance	930 ± 40 ly (290 ± 10 pc)
Details
Radius	300[7] R☉
Luminosity	11,530[8] L☉
Temperature	2,385[8] K
Other designations
R Aur, ADS 3845 A, BD+53 882, CCDM J05173+5335A, GC 6435, HD 34019, HIP 24645, HR 1707, IDS 05092+5328 A, SAO 25112[6]
Database references
SIMBAD	data

In 1862 R Aurigae was found to be a variable star at Bonn Observatory.^[9] It was widely observed in the late 19th century and its spectrum was described in 1890.^[10] In 1907 it appeared with its variable star designation in Annie Jump Cannon's Second Catalogue of Variable Stars.^[9] R Aurigae has an apparent visual magnitude which varies between 6.7 and 13.9 with a period of 450 days.^[3] The light curve varies strongly from cycle to cycle, sometimes having a pronounced hump on the ascending branch and usually having rise and fall times approximately equal. The cycle period has oscillated slowly between about 450 and 465 days.

R Aurigae is catalogued as a component of a double star, with the 10th magnitude HD 233095, although the two stars are unrelated.^[11]