A light curve for V538 Aurigae, plotted from TESS data.[1] The data was folded with the period of 10.86 days which was published by Gaidos et al. (2000).[2]
Eric Gaidos et al. discovered that V538 Aurigae is a variable star based on observations by robotic telescopes[12] at Fairborn Observatory from 1993 through 1999, and they announced their discovery in 2000.[2] The star was given its variable star designation in 2006.[13] This is a BY Draconis variable,[6] 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).[9] It has a spectral class of K1 V, indicating that it is a K-type main sequence star.[5] The star has 87%[7] of the mass of the Sun and 82%[3] of the Sun's radius. It is an estimated 3.76 billion years old.[7] The star is radiating 48% of the Sun's luminosity from its photosphere at an effective temperature of 5,303 K.[3]
It has a common proper motion companion designated Vys 465 (HD 233153),[14] 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.[15]
^Soderblom, David R.; Clements, Sandra D. (April 1987). "Chromospheric and Transition-Region Emission from Young Solar-Type Stars in Clusters, Kinematic Groups, and the Field". The Astronomical Journal. 93: 920–937. Bibcode:1987AJ.....93..920S. doi:10.1086/114378.