AR Aurigae
Based on parallax measurements made by the Hipparcos spacecraft, it is approximately 461 light-years from Earth.[10] Both components are blue-white B-type main-sequence stars that do not fill their Roche lobes.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.[11][12] When an eclipse is not occurring, the star will be faintly visible to the naked eye under very good observing conditions.[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.