First Results from the CHARA Array. I. An Interferometric and Spectroscopic Study of the Fast Rotator α Leonis (Regulus)

Abstract

We report on K-band interferometric observations of the bright, rapidly\nrotating star Regulus (type B7 V) made with the CHARA Array on Mount Wilson,\nCalifornia. Through a combination of interferometric and spectroscopic\nmeasurements, we have determined for Regulus the equatorial and polar diameters\nand temperatures, the rotational velocity and period, the inclination and\nposition angle of the spin axis, and the gravity darkening coefficient. These\nfirst results from the CHARA Array provide the first interferometric\nmeasurement of gravity darkening in a rapidly rotating star and represent the\nfirst detection of gravity darkening in a star that is not a member of an\neclipsing binary system.\n