Evolutionary study of the Be star 28 Tau

We present an evolutionary study of 28 Tau, a Be star, in connection with its rapid rotation. The photometric data during the absence of its envelope in 1921 have been used to determine the effective temperature and luminosity of the star at the main sequence of the HR diagram. From an evolutionary model, we found that the mass and radius of the star are about 3.2 M_solar and 3.2 R_solar respectively. The equatorial rotation velocity of the star, ν_e found to be close to its critical velocity, ν_cr where ν_e/ν_cr ~= 0.87.