Rho Aurigae
Rho Aurigae is a binary star system in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ρ Aurigae, and abbreviated Rho Aur or ρ Aur. This system is faintly visible to the naked eye with an apparent visual magnitude of +5.22. Judging by parallax measurements, this system is approximately distant from the Earth, give or take a 20-light-year margin of error. It is drifting further away from the Sun with a radial velocity of +16 km/s.
ρ Aurigae is a single-lined spectroscopic binary system; the presence of a companion object is revealed by shifts in the stellar spectrum. The pair orbit each other with a period of 34.49 days and an orbital eccentricity of 0.10.
The primary component of this system is a B-type main-sequence star defined as a standard star for the stellar classification of B5 V. The deduced mass of the secondary and the lack of evidence for it in the spectrum suggest it may be a B- or A-type star somewhat less luminous than the primary.