HD 21071
HD 21071 is a blue-white hued variable star in the northern constellation of Perseus. It is a sixth magnitude star that is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 6.09. The brightness of the star varies with a multiperiodic cycle. The distance to HD 21071, as determined from an annual parallax shift of , is 535 light years. It is a member of the young Alpha Persei cluster, Melotte 20, and moving is closer to the Earth with a heliocentric radial velocity of −1.5 km/s. This is a  B-type main-sequence star with a stellar classification of B7 V. HD 21071 belongs to an unusual stellar population termed 'sn' stars. These seem to be related to chemically peculiar stars, but have sharp ('s') Balmer and metal absorption lines with "broad coreless He I" ('n') lines. The latter wide, "nebulous" lines may be due to Stark broadening caused by an electric field. HD 21071 is a slowly pulsating B-type star (SPB star) that was initially found to vary with a period of 0.84 days. Further study revealed four frequencies, with the two dominant, higher amplitude frequencies having  similar cycles of 1.19 and 1.15 per day. Stellar models show the star to have 3.7 times the mass of the Sun, with 2.21 times the Sun's radius. It is 90 million years old with a near-solar metallicity and is spinning with a projected rotational velocity of 58 km/s. The star is radiating 278 times the Sun's luminosity from its photosphere at an effective temperature of 14,768 K.