Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project
Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project
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DOI：
10.3847/1538-4357/aba633
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
A. Meisner;J. Faherty;J. Kirkpatrick;A. Schneider;D. Caselden;J. Gagné;M. Kuchner;A. Burgasser
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文献类型：
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作者：
A. Meisner;J. Faherty;J. Kirkpatrick;A. Schneider;D. Caselden;J. Gagné;M. Kuchner;A. Burgasser
我们目前斯皮策后续成像的95个候选人发现的极冷的棕矮星后院世界：行星9公民科学项目，它使用视觉感知的运动在多时期宽视场红外巡天探测器（WISE）图像，以确定以前未被识别的亚恒星邻居太阳。我们测量斯皮策[3.6]-[4.5]的颜色来拍摄我们的褐矮星候选者，重点是在我们的样本中精确定位最冷和最接近的Y矮星。WISE和斯皮策天体测量的结合提供了我们发现的75个横向运动的定量确认。我们确认的9个天体的最佳线性运动大于1“yr−1;我们发现的最快的是WISEA J155349.96+693355.2（μ π ι 2.”15 yr−1），可能是T型亚矮星。我们还报告了白色LSPM J 0055 +5948（发现的第四个此类系统）的一个新发现的宽分离（400 Au）T8伴星，以及白色LSR J 0002 +6357的一个候选晚T伴星，距离为5.'5预计分离（8700 Au，如果关联）。在我们确认的运动目标中，有五个具有与光谱类型Y最一致的斯皮策颜色。这五个中的四个具有异常红色的斯皮策颜色，表明Y1或更晚的类型，大大增加了这个特别有价值的低温区域中已知物体的小样本。我们的Y矮星候选者开始弥合大部分Y矮星人口和已知最冷的褐矮星之间的差距。
We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]–[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1″ yr−1; our fastest-moving discovery is WISEA J155349.96+693355.2 (μ ≈ 2.″15 yr−1), a possible T-type subdwarf. We also report a newly discovered wide-separation (∼400 au) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5.′5 projected separation (∼8700 au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.