Death throes of giant star puzzle researchers

[Dexter]

http://www.nature.com/news/death-throes-of-giant-star-puzzle-researchers-1.19134?WT.mc_id=FBK_NatureNews

New observations of the bright star Betelgeuse, famous as the shoulder in the constellation of Orion the hunter, raise fresh questions about how it blows huge amounts of gas into interstellar space. Betelgeuse is a red giant near the end of its life, much as the Sun will be billions of years from now. Astronomers study Betelgeuse in hope of understanding the Sun's ultimate fate. But “we now have a problem”, says Graham Harper, an astrophysicist at the University of Colorado Boulder. “If you’re going to eject matter you have to put energy in, and we’re not seeing that.”

Harper and his colleagues used the US–German Stratospheric Observatory for Infrared Astronomy (SOFIA), a 2.5-metre telescope that flies in a modified Boeing 747 aeroplane, to take Betelgeuse’s temperature. They found that the star's upper atmosphere was much cooler than expected — so cool, in fact, that it doesn’t seem to have enough energy to kick gas out of its gravitational pull and into space. “This challenges all our theoretical models,” Harper said on 7 January at a meeting of the American Astronomical Society in Kissimmee, Florida.