Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects
Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects
复制标题
已知最冷的次恒星天体的距离、光度和温度
DOI：
10.1126/science.1241917
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发表时间：
2013
期刊：
影响因子：
56.9
通讯作者：
A. Kraus
中科院分区：
文献类型：
--
作者：
T. Dupuy;A. Kraus
评估褐矮星在过去的两年里，人们已经发现了几十颗非常冷的褐矮星。在300至500开尔文的温度下，褐矮星的质量预计与气体巨行星相当，但由于它们的距离未知，因此无法估计它们的质量。Dupuy和Kraus（第1492页，9月5日在线发表）使用斯皮策太空望远镜的数据测量了非常冷的棕矮星的精确距离，这使他们能够确定矮星的光度，温度和质量。这些结果加强了最冷的褐矮星和气态巨行星之间的联系。斯皮策太空望远镜的观测加强了最冷的褐矮星和气态巨行星之间的联系。已知最冷的褐矮星是太阳系外气体巨行星的最佳类似物。在过去的两年里，对这种冷的亚恒星物体的大量探测激发了密集的后续行动，但缺乏准确的距离是我们理解的一个关键差距。我们提出了一个大样本的精确距离的基础上均匀的中红外天体测量，鲁棒地建立绝对通量，光度和温度。最冷的褐矮星的温度为400至450开，质量几乎等于木星的5至20倍，这表明它们在较热的褐矮星和气态巨行星之间架起了一座差距。在这些极端情况下，光谱能量分布不再遵循与温度的简单对应关系，这表明其他物理参数（如表面重力、垂直混合、云和金属丰度）的作用越来越大。
Assessing Brown Dwarfs The last 2 years have seen the detection of dozens of very cold brown dwarfs. At temperatures around 300 to 500 kelvin, brown dwarfs are expected to have masses comparable to those of gas-giant planets, but because their distances are unknown, it has not been possible to estimate their masses. Dupuy and Kraus (p. 1492, published online 5 September) used data from the Spitzer Space Telescope to measure accurate distances to very cold brown dwarfs, which allowed them to determine the dwarfs' luminosities, temperatures, and masses. The results strengthen the connection between the coolest brown dwarfs and gas-giant exoplanets. Observations with the Spitzer Space Telescope strengthen the link between the coolest brown dwarfs and gas-giant exoplanets. The coolest known brown dwarfs are our best analogs to extrasolar gas-giant planets. The prolific detections of such cold substellar objects in the past 2 years have spurred intensive follow-up, but the lack of accurate distances is a key gap in our understanding. We present a large sample of precise distances based on homogeneous mid-infrared astrometry that robustly establishes absolute fluxes, luminosities, and temperatures. The coolest brown dwarfs have temperatures of 400 to 450 kelvin and masses almost equal to 5 to 20 times that of Jupiter, showing they bridge the gap between hotter brown dwarfs and gas-giant planets. At these extremes, spectral energy distributions no longer follow a simple correspondence with temperature, suggesting an increasing role of other physical parameters, such as surface gravity, vertical mixing, clouds, and metallicity.