Precision measurement of a brown dwarf mass in a binary system in the microlensing event. OGLE-2019-BLG-0033/MOA-2019-BLG-035
Precision measurement of a brown dwarf mass in a binary system in the microlensing event. OGLE-2019-BLG-0033/MOA-2019-BLG-035
复制标题
微透镜事件中双星系统中褐矮星质量的精确测量。
DOI：
10.1051/0004-6361/202243490
复制
发表时间：
2022
影响因子：
6.5
通讯作者：
D. et al.
中科院分区：
文献类型：
--
作者：
Herald;A. ; Udalski;A. ; Bozza;V. and Suzuki;D. et al.
褐矮星是恒星和行星之间的过渡天体，人们对它的了解仍然很少，已经提出了几种相互竞争的机制来描述它们的形成。对于孤立的天体和围绕低质量恒星运行的褐矮星，质量测量通常很难进行，因为它们通常太微弱，无法进行光谱跟踪。AimsMicrolensing为发现和研究这种微弱系统提供了一种替代工具。在这里，我们提出了一个微透镜事件OGLE-2019-BLG-0033/MOA-2019-BLG-035的分析，这是由一个由褐矮星轨道红矮星组成的双星系统引起的。方法由于广泛的地面观测和斯皮策太空观测的可用性，已经可以获得所有微透镜参数的准确估计，包括视差，源半径，结果通过精确的模型计算，我们发现该双星透镜是由一颗质量为M1 = 0.149 ± 0.010M的红矮星和一颗质量为M2 = 0.0463 ± 0.0031M的棕矮星组成，投影距离为Au。该系统有一个特殊的速度，这是典型的旧金属贫人口在厚盘。到目前为止，褐矮星质量测量的精确度只有在少数微透镜事件中才能达到，但由于罗马太空望远镜，未来可能会变得更加普遍。
ContextBrown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up.AimsMicrolensing provides an alternative tool for the discovery and investigation of such faint systems. Here, we present an analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is caused by a binary system composed of a brown dwarf orbiting a red dwarf.MethodsThanks to extensive ground observations and the availability of space observations fromSpitzer,it has been possible to obtain accurate estimates of all microlensing parameters, including the parallax, source radius, and orbital motion of the binary lens.ResultsFollowing an accurate modeling process, we found that the lens is composed of a red dwarf with a mass ofM1= 0.149 ± 0.010M⊙and a brown dwarf with a mass ofM2= 0.0463 ± 0.0031M⊙at a projected separation ofa⊥= 0.585 au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. A percent-level precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become more common in the future thanks to theRomanspace telescope.