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arXiv · 0911.1127

Discovery of the Coldest Imaged Companion of a Sun-Like Star

Christian Thalmann·Joseph Carson·Markus Janson·Miwa Goto·Michael McElwain·Sebastian Egner·Markus Feldt·Jun Hashimoto·Yutaka Hayano·Thomas Henning·Klaus W. Hodapp·Ryo Kandori·Hubert Klahr·Tomoyuki Kudo·Nobuhiko Kusakabe·Christoph Mordasini·Jun-Ichi Morino·Hiroshi Suto·Ryuji Suzuki·Motohide Tamura
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Abstract

We present the discovery of a brown dwarf or possible planet at a projected separation of 1.9" = 29 AU around the star GJ 758, placing it between the separations at which substellar companions are expected to form by core accretion (~5 AU) or direct gravitational collapse (typically >100 AU). The object was detected by direct imaging of its thermal glow with Subaru/HiCIAO. At 10-40 times the mass of Jupiter and a temperature of 550-640 K, GJ 758 B constitutes one of the few known T-type companions, and the coldest ever to be imaged in thermal light around a Sun-like star. Its orbit is likely eccentric and of a size comparable to Pluto's orbit, possibly as a result of gravitational scattering or outward migration. A candidate second companion is detected at 1.2" at one epoch.

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Christian Thalmann, Joseph Carson, Markus Janson, Miwa Goto, Michael McElwain, Sebastian Egner, Markus Feldt, Jun Hashimoto, Yutaka Hayano, Thomas Henning, Klaus W. Hodapp, Ryo Kandori, Hubert Klahr, Tomoyuki Kudo, Nobuhiko Kusakabe, Christoph Mordasini, Jun-Ichi Morino, Hiroshi Suto, Ryuji Suzuki, Motohide Tamura. 2009-11-05. Discovery of the Coldest Imaged Companion of a Sun-Like Star. https://doi.org/10.1088/0004-637x/707/2/l123

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