An Etymological Dictionary of Astronomy and Astrophysics

The → angular velocity of a star deduced from the → rotational broadening of its → spectral lines. It is expressed as v sini, where i is the → inclination of the rotational axis with respect to the normal to the → plane of the sky. The real equatorial rotational velocity can be determined only if the inclination of the rotational axis is known.

See also: Projected, p.p. of → project; → rotational; → velocity.