标题： WISEP J180026.60+013453.1附近的棕矮星的特性 显示英文标题

标题： Properties of the Nearby Brown Dwarf WISEP J180026.60+013453.1

摘要： 我们提供了新的光谱和天体测量数据来表征附近的棕矮星 WISEP J180026.60+013453.1。 光学光谱类型为 L7.5，与之前报告的近红外光谱类型一致。 初步的三角视差表明其距离为$8.01 \pm 0.21$pc，确认它是第四近的晚期 L（L7-L9）矮星。 测得的光度、我们对锂的检测以及缺乏低表面重力指标表明，根据理论次恒星演化模型，WISEP J180026.60+013453.1 的质量为$0.03 < M < 0.06 M_\odot$，并且年龄在 3 亿到 15 亿年之间。 低空间运动与这个年轻年龄一致。 我们测得了旋转展宽（$v \sin i = 13.5 \pm 0.5$km/s），并用它估计了最大旋转周期为 9.3 小时。 显示英文摘要

摘要： We present new spectroscopy and astrometry to characterize the nearby brown dwarf WISEP J180026.60+013453.1. The optical spectral type, L7.5, is in agreement with the previously reported near-infrared spectral type. The preliminary trigonometric parallax places it at a distance of $8.01 \pm 0.21$ pc, confirming that it is the fourth closest known late-L (L7-L9) dwarf. The measured luminosity, our detection of lithium, and the lack of low surface gravity indicators indicates that WISEP J180026.60+013453.1 has a mass $0.03 < M < 0.06 M_\odot$ and an age between 300 million and 1.5 billion years according to theoretical substellar evolution models. The low space motion is consistent with this young age. We have measured the rotational broadening ($v \sin i = 13.5 \pm 0.5$ km/s), and use it to estimate a maximum rotation period of 9.3 hr.