Tau2 Arietis
Tau2 Arietis is a binary star system in the northern constellation on Aries. Its name is a Bayer designation that is Latinized from τ2 Arietis, and abbreviated Tau2 Ari or τ2 Ari. The combined apparent visual magnitude of this system is +5.09, which is bright enough to be seen with the naked eye. With an annual parallax shift of, it is located at a distance of approximately from Earth, give or take an 8 light-year margin of error. At this distance the brightness of the star is diminished by 0.18 in magnitude because of extinction from interstellar gas and dust. The system is receding from the Sun with a radial velocity of +2.5 km/s.
The primary component is an evolved giant star with a stellar classification of K3 III. It is an estimated 1.6 billion years old and is spinning with a projected rotational velocity of 3.4 km/s. With double the mass of the Sun, it has expanded to 19 times the radius of the Sun. The star is radiating 120 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,406 K, giving it the cool orange glow of a K-type star. At an angular separation of 0.53 arcseconds is a magnitude 8.50 companion.