FIVE enigmatic stars in a cluster at the heart of the Milky Way have puzzled astronomers for more than a decade. For stars of their brightness, they seemed extraordinarily cool and dusty. Now, the five have turned out to be massive double stars, blowing dust into elegant pinwheel shapes as they live fast and die young.
The Quintuplet cluster, so named for its five prominent dust-shrouded red stars, lies about 26,000 light years from us. Peter Tuthill of the University of Sydney in Australia and his team used one of the twin 10-metre Keck telescopes on Mauna Kea, Hawaii, to create detailed infrared images of the quints and found dust lanes in a clear spiral around at least two of them.
The best explanation, they say, is that each dusty cocoon contains two stars, at least one of which is a rare and massive 鈥淲olf-Rayet鈥� star spewing violent winds at 2000 kilometres per second. This wind is colliding with slower wind from the other giant star (Science, vol 313, p 935). Dense cool dust forms in the region where the two winds collide, and this spreads outwards in a spiral as the two stars circle each other. 鈥淵ou have an effect like a garden hose being twirled around,鈥� says team member Donald Figer from the Rochester Institute of Technology, New York.
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Figer says the Wolf-Rayet stars will soon blow themselves to smithereens: 鈥淚t鈥檚 the last stage before they go supernova, probably within a few hundred thousand years.鈥�
