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arXiv 1107.0768astro-ph.SR
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发现两颗具有宽间隔和特殊光度特性的L & T双星

Discovery of two L & T binaries with wide separations and peculiar photometric properties

Étienne Artigau, David Lafrenière, René Doyon, Michael Liu, Trent J. Dupuy, Loïc Albert, Jonathan Gagné, Lison Malo, Damien Gratadour

摘要:

我们目前的空间分辨光度和光谱观测发现的两个宽棕矮星双星的SIMP近红外自行调查。第一对(SIMP J1619275+ 031350 AB)的分离度为0.691”(15.2 AU),成分为T2.5+T4.0,位于不清楚的J带增亮的较冷端。该系统是不寻常的,因为较早类型的主要是蓝色的J-KS比后来类型的中学,而相反的是预计在晚L到T矮星范围的双星。这种显着的颜色反转可能是由两个组成部分之间非常不同的云属性来解释的。第二对(SIMP J1501530- 013506 AB)由L4.5+L5.5(分离度0.96”,30-47 AU)组成,考虑到其组分的相似光谱类型,具有令人惊讶的大通量比(Δ J =1.79 mag)。如果主星本身是一颗等光度的双星,那么大的流量比可以解释,这将使它成为第一个已知的三重棕矮星系统之一。自适应光学观测不能证实这一假设,但它仍然是一个可能的,这可能是由高分辨率近红外光谱验证。这两个系统添加到少数已知的褐矮星双星服从分辨光谱学没有自适应光学的帮助,并构成主要目标,以测试褐矮星大气模型。

英文摘要:

We present spatially resolved photometric and spectroscopic observations of two wide brown dwarf binaries uncovered by the SIMP near-infrared proper motion survey. The first pair (SIMP J1619275+031350AB) has a separation of 0.691" (15.2 AU) and components T2.5+T4.0, at the cooler end of the ill-understood J-band brightening. The system is unusual in that the earlier-type primary is bluer in J-Ks than the later-type secondary, whereas the reverse is expected for binaries in the late-L to T dwarf range. This remarkable color reversal can possibly be explained by very different cloud properties between the two components. The second pair (SIMP J1501530-013506AB) consists of an L4.5+L5.5 (separation 0.96", 30-47 AU) with a surprisingly large flux ratio (Delta J =1.79 mag) considering the similar spectral types of its components. The large flux ratio could be explained if the primary is itself an equal-luminosity binary, which would make it one of the first known triple brown dwarf systems. Adaptive optics observations could not confirm this hypothesis, but it remains a likely one, which may be verified by high-resolution near-infrared spectroscopy. These two systems add to the handful of known brown dwarf binaries amenable to resolved spectroscopy without the aid of adaptive optics and constitute prime targets to test brown dwarf atmosphere models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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