论文标题
KMT-2018-BLG-0748LB：旋转Ultracool宿主
KMT-2018-BLG-0748Lb: Sub-Saturn Microlensing Planet Orbiting an Ultracool Host
论文作者
论文摘要
我们宣布发现了微透镜行星系统，其中亚星期行星正在绕着超级矮人的宿主行驶。我们通过分析短期计（$ t _ {\ rm e} \ sim 4.4 $〜天）镜头事件KMT-2018-BLG-0748来检测行星系统。光曲线的中心部分由于上升部分的负偏差以及下降部分的正偏差而表现出不对称性。我们发现偏差是通过二进制镜头模型解释的，其镜头组件$ q \ sim 2 \ times 10^{ - 3} $之间的质量比。简短的事件时间尺度与小的角度爱因斯坦半径，$θ_ {\ rm e} \ sim 0.11 $ 〜mas，表明行星主体的质量很小。假设行星频率独立于宿主质量的假设进行的贝叶斯分析表明，行星的质量为$ m _ {\ rm p} = 0.18^{+0.29} _ { - 0.10} 〜m _ {\ m _ {\ rm j} $，以及宿主的群体0.087^{+0.138} _ { - 0.047} 〜m_ \ odot $在星/棕色矮人边界附近，但是估计的宿主质量对行星托管概率的假设敏感。高分辨率随访观察结果将导致揭示行星宿主的性质。
We announce the discovery of a microlensing planetary system, in which a sub-Saturn planet is orbiting an ultracool dwarf host. We detect the planetary system by analyzing the short-timescale ($t_{\rm E}\sim 4.4$~days) lensing event KMT-2018-BLG-0748. The central part of the light curve exhibits asymmetry due to the negative deviations in the rising part and the positive deviations in the falling part. We find that the deviations are explained by a binary-lens model with a mass ratio between the lens components of $q\sim 2\times 10^{-3}$. The short event timescale together with the small angular Einstein radius, $θ_{\rm E}\sim 0.11$~mas, indicate that the mass of the planet host is very small. The Bayesian analysis conducted under the assumption that the planet frequency is independent of the host mass indicates that the mass of the planet is $M_{\rm p}=0.18^{+0.29}_{-0.10}~M_{\rm J}$, and the mass of the host, $M_{\rm h}= 0.087^{+0.138}_{-0.047}~M_\odot$, is near the star/brown dwarf boundary, but the estimated host mass is sensitive to the assumption about the planet hosting probability. High-resolution follow-up observations would lead to revealing the nature of the planet host.
