文章基本信息

标题：KMT-2018-BLG-1988Lb: Microlensing super-Earth orbiting a low-mass disk dwarf
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作者：Cheongho Han ; Andrew Gould ; Michael D.Albrow 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2022
卷号：658
页码：1-8
DOI：10.1051/0004-6361/202142077
语种：English
出版社：EDP Sciences
摘要：Aims. We reexamine high-magnification microlensing events in the previous data collected by the KMTNet survey with the aim of finding planetary signals that were not noticed before. In this work, we report the planetary system KMT-2018-BLG-1988L, which was found from this investigation. Methods. The planetary signal appears as a deviation with ≲0.2 mag from a single-lens light curve and lasted for about 6 h. The deviation exhibits a pattern of a dip surrounded by weak bumps on both sides of the dip. The analysis of the lensing light curve indicates that the signal is produced by a low-mass-ratio (q ~ 4 × 10−5) planetary companion located near the Einstein ring of the host star. Results. The mass of the planet, Mplanet = 6.8−3.5+4.7 M⊕ and 5.6−2.8+3.8 M⊕ for the two possible solutions, estimated from the Bayesian analysis indicates that the planet is in the regime of a super-Earth. The host of the planet is a disk star with a mass of Mhost = 0.47−0.25+0.33 M⊙ and a distance of DL = 4.2−.14+1.8 kpc. KMT-2018-BLG-1988Lb is the 18th known microlensing planet with a mass below the upper limit of a super-Earth. The fact that 15 out of the 18 known microlensing planets with masses ≲10 M⊕ were detected in the 5 yr following the full operation of the KMTNet survey indicates that the KMTNet database is an important reservoir of very low-mass planets.
关键词：gravitational lensing: micro;planets and satellites: detection