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Paper: CHARA Array Observations of Be Stars and Regulus (Invited Talk)
Volume: 361, Active OB-Stars: Laboratories For Stellar and Circumstellar Physics
Page: 307
Authors: Gies, D.R.; Baines, E.K.; Berger, D.H.; Farrington, C.; Grundstrom, E.D.; Huang, W.; McAlister, H.A.; ten Brummelaar, T.A.
Abstract: The disks of Be stars produce an infrared flux excess that is predicted to have an angular size much larger than the stellar diameter in the sky. Here we report on the first K-band long baseline interferometric observations of Be stars made with the CHARA Array on Mount Wilson, California. We present observations of the Be stars Phi Per, Zeta Tau, Gamma Cas, and Kappa Dra that clearly reveal the disk flux, and we use simple disk models to fit the interferometric visibilities.

We also report on CHARA K-band observations of the bright, rapidly rotating star Regulus (type B7 V). Through a combination of interferometric and spectroscopic measurements, we have determined for Regulus the equatorial and polar diameters and temperatures, the rotational velocity and period, the inclination and position angle of the spin axis, and the gravity darkening coefficient. These results provide the first interferometric measurement of gravity darkening in a rapidly rotating star and represent the first detection of gravity darkening in a star that is not a member of an eclipsing binary system.

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