The Week in SpaceDecember 7-13, 2009
Like Candles on the Moon The Hubble Space Telescope has revealed some of the dimmest stars ever seen in globular clusters, those tight groupings of hundreds of thousands of stars that formed early in the Universe’s 14 billion year history. Hubble studied NGC 6397, a globular cluster 8,500 light-years from Earth, and surveyed the faintest red dwarf stars (which still fuse hydrogen in their cores) and the dimmest white dwarfs (burned-out relics of normal stars up to eight times the mass of the Sun). The light from these faint stars is as dim as the light from a birthday candle on the Moon would be if seen from Earth, and they are barely visible here as faint dots. Stars that were initially even more massive died as supernovae very early in the cluster’s life, leaving behind neutron stars, black holes, or no debris at all. Image credit: NASA, ESA, and H. Richer (University of British Columbia) Weekly CalendarDecember 7-13, 2009Holidays - Sky Events - Space History 1905: Gerard Kuiper born |
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