Phi1 Lupi

Phi¹ Lupi is a solitary star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.58. Based upon an annual parallax shift of 11.86 mas as seen from Earth, it is located around 275 light years from the Sun.

This is an evolved K-type giant star with a stellar classification of K5 III, which means it has used up its core hydrogen and has expanded. The measured angular diameter, after correction for limb darkening, is 7000569000000000000♠5.69±0.07 mas. At the estimated distance of Phi¹ Lupi, this yields a physical size of about 52 times the radius of the Sun. It is a variable star of unknown type, with an amplitude of 0.008 in visual magnitude and a period of 4.82 days.