Epsilon Aurigae: A Supergiant and a Super Disk

Extract

The eclipsing binary Epsilon Aurigae consists of an F0 supergiant and a cool, mysterious eclipsing companion with an orbital period of 27.1 years. The light curve of this system reveals two sources of variability: the eclipses themselves and the intrinsic variation of the supergiant. Multifilter photoelectric observations were made with the 38 cm reflector at the Villanova University Observatory. These data were analyzed along with other sources to reveal the nature of the components of the Epsilon Aurigae system. The system undergoes low-amplitude semi-regular light variations with a characteristic period of 110 days and perhaps a longer period of 500-600 days. The proximity of Epsilon Aur to the Cepheid instability strip on the H-R diagram suggests that the pulsation mechanism for this star may be similar to that of Cepheids.