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11 Arietis has a stellar classification of B9 IV-Vn, which may indicate that it is beginning to evolve away from the main sequence into a subgiant as the supply of hydrogen at its core becomes exhausted. At present, it has an estimated radius of 2.8 times that of the Sun, but this will increase as it continues to evolve into a giant star. 11 Arietis is spinning rapidly with a projected rotational velocity of 249 km/s. This motion, combined with the Doppler effect, is causing the absorption lines in the spectrum to spread out and become 'nebulous', as indicated by the 'n' suffix in the classification.
^ Crawford, D. L. (February 1963), "U, b, v, and Hβ Photometry for the Bright B8- and B9-TYPE Stars", Astrophysical Journal, 137: 530, Bibcode:1963ApJ...137..530C, doi:10.1086/147526.