Upsilon1 Eridani

Upsilon¹ Eridani (υ¹ Eri) is a single star in the constellation Eridanus. It has an apparent visual magnitude is 4.51, which is bright enough to be faintly visible to the naked eye on a clear, dark night. The distance to this star, as determined using the parallax method, is around 127 light years.

This is an evolved red clump giant star with a stellar classification of K0III-IV. The measured angular diameter, after correction for limb darkening, is 1.74±0.02 mas. At an estimated distance of this star, this yields a physical size of about 7.3 times the radius of the Sun. It has 154% of the Sun's mass and radiates 24 times the solar luminosity from its outer atmosphere at an effective temperature of 4,941 K.