The Infrared Angular Diameter of Alpha Herculis Measured With a Michelson Interferometer
Abstract
The first infrared angular diameter measurements of Alpha Her, a bright cool supergiant are presented. The measurements are the first astronomical scientific results from the infrared Michelson array, a prototype near-infrared, broadband, two-telescope interferometer. Visibilities obtained with telescope separations of 4.8, 8.0, and 12.0 m are reported. The data were fit with both uniform disk and limb darkened models. It is found that the uniform disk angular diameter of Alpha Her at 2.2 microns is 32.2 +/-0.8 marcsec. By using the limb darkening models of Sholz and Takeda (1987) and the present angular diameter measurement, a stellar physical angular diameter of 34 +/-0.8 marcsec is derived. From this determined stellar angular diameter and a compilation of flux measurements from the literature, it is further determined that the effective temperature of Alpha Her is 3210 +/-40 K.
- Publication:
-
The Astronomical Journal
- Pub Date:
- December 1991
- DOI:
- 10.1086/116033
- Bibcode:
- 1991AJ....102.2091B
- Keywords:
-
- Astrometry;
- Infrared Stars;
- Michelson Interferometers;
- Supergiant Stars;
- Angular Resolution;
- Diameters;
- Infrared Telescopes;
- Stellar Temperature;
- Astronomy;
- STARS: SUPERGIANTS;
- INTERFEROMETRY