111 Tauri

111 Tauri is a wide binary star system in the constellation Taurus. It is located at a distance of about 47 light years from the Sun. Primary component A is a main sequence star with a stellar classification of F8V. The secondary component B (Gliese 201) is a K-type main sequence star. It is larger and more luminous than the Sun, with about 130% of the Sun's radius and 185% of the Sun's luminosity. The apparent magnitude of 5.1 indicates it is a faint star that can be viewed by the naked eye under good, dark-sky conditions.

The metallicity of the primary star, which measures the proportion of elements other than hydrogen and helium, is similar to the Sun. Estimates of [Fe/H], which is the logarithm of the ratio of iron to hydrogen as compared to the Sun, range from a low of −0.14 to a high of 0.05. This star shows an unusually high content of Lithium, which remains unexplained. Age estimates for this star range from 3.6 to 3.76 billion years. It is a prominent X-ray source.

This star is rotating relatively rapidly, completing a rotation along the equator every 4.1 days as compared to 25 days for the Sun. It is also undergoing differential rotation in which the rotation velocity varies by latitude.

This star was examined for an excess of infrared emission that could indicate it has a circumstellar debris disk of dust, but no significant excess was observed. The space velocity components of this star are [U, V, W] = [−36.94, −14.63, 7.63] km/s. It shares a common proper motion with HIP 25220, an active star with stellar classification K4V. Both stars are members of the Hyades stellar kinematic group of co-moving stars.