V538 Aurigae

V538 Aurigae is a single star in the northern constellation of Auriga. With an apparent visual magnitude of about 6.2, this star requires good dark sky conditions to view with the naked eye. It is located at a distance of 40.0 light-years (12.3 pc) from Sun based on parallax. The star is drifting further away with a radial velocity of 0.9 km/s. It is a member of the Local Association, and is most likely a thin disk star.

Eric Gaidos et al. discovered that V538 Aurigae is a variable star based on observations by robotic telescopes at Fairborn Observatory from 1993 through 1999, and they announced their discovery in 2000. The star was given its variable star designation in 2006. This is a BY Draconis variable, which means it undergoes changes in luminosity because regions of pronounced surface magnetic activity are moved into and out of the line of sight from the Earth as the star rotates (once every 11 days). It has a spectral class of K1 V, indicating that it is a K-type main sequence star. The star has 87% of the mass of the Sun and 82% of the Sun's radius. It is an estimated 3.76 billion years old. The star is radiating 48% of the Sun's luminosity from its photosphere at an effective temperature of 5,303 K.

It has a common proper motion companion designated Vys 465 (HD 233153), which is a red dwarf with a class of M0.5V and a visual magnitude of 9.87. Their projected separation is 1,204 AU.