Tau Aurigae
Tau Aurigae is a star in the northern constellation Auriga. Its name is a Bayer designation that is Latinized from τ Aurigae, and abbreviated Tau Aur or τ Aur. This star is visible to the naked eye with an apparent visual magnitude of 4.5 and is positioned about a half degree west of the brighter star Nu Aurigae. Based on parallax measurements, it is approximately distant from Earth. The star is drifting closer to the Sun with a radial velocity of −19 km/s.
Tau Aurigae is an evolved giant star with a stellar classification of, which indicates it has exhausted the supply of hydrogen at its core and expanded off the main sequence of Sun-like stars. The 'Fe-1' notation indicates that the stellar spectrum has anomalously weak lines of iron. This star is an estimated million years old and is spinning with a projected rotational velocity of 3.8 km/s. With 2.6 times the mass of the Sun, it has 11 times the Sun's radius and shines with 63 times the Sun's luminosity. This energy is radiated into outer space from the photosphere at an effective temperature of 4,887 K. This heat gives it the yellow-hued glow of a G-type star.