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Program Number
Program Name Searching for a Possible Black Hole in BG Geminorum                      
Scott Kenyon  [email]  [web]  
Co-Investigator(s) Priscilla Benson, Paul Groot, Alceste Bonanos, Kim McLeod and Allyn Dullinghan


BG Gem is a rare type of eclipsing binary system with an orbital period of 91.6 days. The two component stars of this binary are a distorted supergiant star and an unseen companion surrounded by a swirling disk of hot gas. The invisible star has a mass nearly 5 times larger than the Sun and is roughly 10 times more massive than its cooler companion. The gravity of the massive star distorts the shape of the supergiant and causes it to lose mass into the disk. Material in the disk gets hotter and hotter as it approaches the massive star at the center of the disk. Eventually this material falls onto the massive star, perhaps producing ultraviolet radiation or X-rays. We are trying to discern the nature of the unseen massive star in BG Gem.

Is it a hot main sequence star hidden by the edge of the disk?

Or, is it a black hole?
Spectra [search in archive]
Trimester(s) data taken 1998c-2003c
Papers 2000, AJ, 119, 890
2002, AJ, 124, 1054

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BG Geminorum

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