ULAS J141623.94$ + $134836.3 - a faint common proper motion companion of a nearby L dwarf. Serendipitous discovery of a cool brown dwarf in UKIDSS DR6
ULAS J141623.94$ + $134836.3 - a faint common proper motion companion of a nearby L dwarf. Serendipitous discovery of a cool brown dwarf in UKIDSS DR6
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ULAS J141623.94$ 134836.3 - 附近一颗 L 矮星的微弱常见自行伴星。
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
R. Scholz
中科院分区：
文献类型：
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作者：
R. Scholz
目标。新的近红外大面积巡天（如UKIDSS、CFBDS、WISE）比2 MASS更深入，目的是探测潜伏在太阳附近的褐矮星，这些褐矮星甚至比最新已知的T型天体（所谓的Y矮星）还要暗。方法.使用UKIDSS数据，我们发现了一颗微弱的棕矮星候选者，具有非常红色的光学到近红外，但在最近发现的附近L矮星SDSS J141624.08+134826.7旁边有极蓝色的近红外颜色。我们通过研究它们的视差和自行来检查这两个物体是否共同运动，并将新物体与已知的T矮星进行比较。结果天体测量结果与距离d ≈ 8秒差距处的物理对（sep ≈ 75 Au）一致。极端的颜色（J −K <$− 1.7）和绝对星等（MJ = 17.78 ± 0.46和MK = 19.45 ± 0.52）使这个新天体看起来是最冷的（Teff <$600 K）和最近的棕矮星之一，可能是晚T光谱类型，可能有高表面重力（log g <$5.0）。
Aims. New near-infrared large-area sky surveys (e.g. UKIDSS, CFBDS, WISE) go deeper than 2MASS and aim at detecting brown dwarfs lurking in the solar neighbourhood that are even fainter than the latest known T-type objects, so-called Y dwarfs. Methods. Using UKIDSS data, we found a faint brown dwarf candidate with very red optical-to-near-infrared, but extremely blue near-infrared colours next to the recently discovered nearby L dwarf SDSS J141624.08+134826.7. We checked if the two objects are co-moving by studying their parallactic and proper motion and compared the new object with known T dwarfs. Results. The astrometric measurements are consistent with a physical pair (sep ≈ 75 AU) at a distance d ≈ 8 pc. The extreme colour (J −K ≈− 1.7) and absolute magnitude (MJ = 17.78 ± 0.46 and MK = 19.45 ± 0.52) make the new object appear as one of the coolest (Teff ≈ 600 K) and nearest brown dwarfs, probably of late-T spectral type and possibly with a high surface gravity (log g ≈ 5.0).