Discovery of a cool brown dwarf
Discovery of a cool brown dwarf
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DOI：
10.1038/378463a0
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发表时间：
1995-11
期刊：
影响因子：
64.8
通讯作者：
T. Nakajima;B. Oppenheimer;S. Kulkarni;D. Golimowski;K. Matthews;S. Durrance
中科院分区：
文献类型：
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作者：
T. Nakajima;B. Oppenheimer;S. Kulkarni;D. Golimowski;K. Matthews;S. Durrance
棕矮星是质量小于太阳0.08倍的恒星状天体，它们无法在其星系中维持氢聚变1 -4。它们很难被探测到，因为大部分引力收缩的能量都在108 yr内被辐射出去，只留下很低的剩余光度。因此，几乎所有对褐矮星的搜索都是针对年轻恒星的星团，这一策略最近被证明是成功的。但是，在年轻的褐矮星和质量非常低的恒星之间只有适度的可观测差异，因此很难在不诉诸复杂模型的情况下识别前者。年长的棕矮星应该有更独特的外观，如果它们是附近恒星的伴星，它们的光度可以明确地确定。在这里，我们报告发现了附近星星G1229的一个可能的伴星，它的光度不超过最不亮的氢燃烧星星的十分之一。我们的结论是，伴星G1229 B是一颗褐矮星，温度低于1,200 K，质量是木星的20-50倍。
BROWN dwarfs are starlike objects with masses less than 0.08 times that of the Sun, which are unable to sustain hydrogen fusion in their interiors1–4. They are very hard to detect, as most of the energy of gravitational contraction is radiated away within ∼108yr, leaving only a very low residual luminosity. Accordingly, almost all searches for brown dwarfs have been directed towards clusters of young stars—a strategy that has recently proved successful5,6. But there are only modest observable differences between young brown dwarfs and very lowmass stars, making it difficult to identify the former without appealing to sophisticated models7. Older brown dwarfs should have a more distinctive appearance, and if they are companions to nearby stars, their luminosity can be determined unambiguously. Here we report the discovery of a probable companion to the nearby star G1229, with no more than onetenth the luminosity of the least luminous hydro-gen-burning star. We conclude that the companion, G1229B, is a brown dwarf with a temperature of less than 1,200 K, and a mass ∼20–50 times that of Jupiter.