Amateur Astronomers Spot One In A Billion Star: Gaia 14 aae; No Hydrogen
http://www.sciencedaily.com/releases/2015/07/150716205413.htm
Date: July 16, 2015
Source: University of Cambridge
Summary: The Gaia satellite has discovered a unique binary system where one star is eating the other, but neither star has any hydrogen, the most common element in the Universe. The system could be an important tool for understanding how binary stars might explode at the end of their lives.
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Using spectroscopy from the William Herschel Telescope in the Canary Islands, Campbell and her colleagues found that Gaia14aae contains large amounts of helium, but no hydrogen, which is highly unusual as hydrogen is the most common element in the Universe. The lack of hydrogen allowed them to classify Gaia14aae as a very rare type of system known as an AM Canum Venaticorum (AM CVn), a type of Cataclysmic Variable system where both stars have lost all of their hydrogen. This is the first known AM CVn system where one star totally eclipses the other.
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Expansion of the Universe?