Epsilon Eridani (ε Eri / ε Eridani) is a main-sequence star of spectral class K2. Only 10.5 light years away, it is the closest star in the constellation Eridanus, as well as the third closest star visible to the naked eye. Its age is estimated at less than a billion years. Because of its relative youth, Epsilon Eridani has a higher level of magnetic activity than the Sun, with a stellar wind 30 times as strong. Its rotation period is a relatively rapid 11.1 days, although this varies by latitude. Epsilon Eridani is both smaller and less massive than the Sun, with a lower metallicity.