TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis-猫眼课题宝

DOI：

10.1051/0004-6361/202038934

发表时间：

2020-11

期刊：

Astronomy & Astrophysics

影响因子：

6.5

通讯作者：

中科院分区：

物理与天体物理2区

文献类型：

作者：

H. Parviainen;E. Pallé;M. Zapatero-Osorio;G. Nowak;A. Fukui;F. Murgas;N. Narita;K. Stassun;J. Livingston;K. Collins;D. H. Soto;V. B'ejar;J. Korth;M. Monelli;P. M. Rodríguez;N. Casasayas-Barris;G. Chen;N. Crouzet;J. D. Leon;A. Hernández;K. Kawauchi;P. Klagyivik;N. Kusakabe;R. Luque;M. Mori;T. Nishiumi;J. Prieto-Arranz;M. Tamura;N. Watanabe;T. Gan;K. Collins;E. Jensen;T. Barclay;J. Doty;J. Jenkins;D. Latham;M. Paegert;G. Ricker;D. Rodriguez;S. Seager;Avi Shporer;R. Vanderspek;J. Villasenor;J. Winn;B. Wohler;I. Wong

上下文我们发现了TOI-519 B（TIC 218795833），它是一个在1.26 d轨道上绕着一颗暗M矮星（V = 17.35）运行的凌日亚星天体（R = 1.07 RJup）。棕矮星和大质量行星在短周期轨道上围绕M矮星运行是罕见的，但已经发现了比行星形成模型预期的更多。TOI-519是对这组不太可能的系统的宝贵补充，它增加了我们对行星形成边界的理解。目标。我们着手确定凌日系外行星勘测卫星（TESS）感兴趣的TOI-519 B的性质。方法.我们的分析使用了来自第7区的SPOC管道TESS光变曲线，用MuSCAT 2和MuSCAT观测到的多色凌日测光，以及用LCOGT望远镜观测到的凌日测光。我们使用多色过境模型估计过境物体的半径，并使用相位曲线模型（包括多普勒增强、椭球变化、热发射和反射光分量）设置其质量、有效温度和邦德散射的上限。结果TOI-519 B是一个亚恒星天体，后中值半径为1.07 RJup，第5和第95位半径分别为0.66和1.20 RJup，其中大部分的不确定性来自恒星半径的不确定性。相曲线分析设定了1800 K的有效温度上限，0.49的邦德最大极限，以及14兆焦耳的伴随质量上限。伴星的半径估计结合Teff和质量极限表明伴星更有可能是行星而不是棕矮星，但棕矮星的可能性更大，因为缺乏已知的大质量行星在Teff < 3800 K的M矮星周围的201天轨道上，并且存在一些（但很少）棕矮星。

Context. We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered than expected from planet formation models. TOI-519 is a valuable addition to this group of unlikely systems, and it adds towards our understanding of the boundaries of planet formation. Aims. We set out to determine the nature of the Transiting Exoplanet Survey Satellite (TESS) object of interest TOI-519 b. Methods. Our analysis uses a SPOC-pipeline TESS light curve from Sector 7, multicolour transit photometry observed with MuSCAT2 and MuSCAT, and transit photometry observed with the LCOGT telescopes. We estimated the radius of the transiting object using multicolour transit modelling, and we set upper limits for its mass, effective temperature, and Bond albedo using a phase curve model that includes Doppler boosting, ellipsoidal variations, thermal emission, and reflected light components. Results. TOI-519 b is a substellar object with a radius posterior median of 1.07 RJup and 5th and 95th percentiles of 0.66 and 1.20 RJup, respectively, where most of the uncertainty comes from the uncertainty in the stellar radius. The phase curve analysis sets an upper effective temperature limit of 1800 K, an upper Bond albedo limit of 0.49, and a companion mass upper limit of 14 MJup. The companion radius estimate combined with the Teff and mass limits suggests that the companion is more likely a planet than a brown dwarf, but a brown-dwarf scenario is a priori more likely given the lack of known massive planets in ≈ 1 day orbits around M dwarfs with Teff < 3800 K, and given the existence of some (but few) brown dwarfs.

TOI-519 b: A short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis

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