We present the latest astronomical results from the Cambridge Optical Aperture Synthesis Telescope (COAST). COAST is a first-generation stellar interferometer, which uses an array of small (40 cm) separated telescopes to perform high-resolution imaging at visible and near-infrared wavelengths. The new science results from COAST exploit two recently-added capabilities of the COAST array, namely the ability to observe in any over the infrared J, H and K bands as well as at visible wavelengths, plus operation with five telescopes. We present contemporaneous observations of the red supergiant Betelgeuse at three wavelengths in the red and near-infrared. These data show that the apparent symmetry of the stellar disk is a strong function of wavelength, but that the bright spots seen in visible light are consistent with a convective origin. Data obtained using all five array elements on the symbiotic star CH Cygni reveal an elliptical distortion of the disk of the red giant, possibly related to mass transfer of a compact companion.

Date Published: 5 July 2000
PDF: 9 pages
Proc. SPIE 4006, Interferometry in Optical Astronomy, (5 July 2000); doi: 10.1117/12.390242

Published in SPIE Proceedings Vol. 4006:
Interferometry in Optical Astronomy
Pierre J. Lena; Andreas Quirrenbach, Editor(s)