Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf
Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf
复制标题
对附近 M3 矮星周围的亚海王星 TOI-2136b 进行验证和大气探索
DOI：
10.1051/0004-6361/202243381
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发表时间：
2022
影响因子：
6.5
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
Kawauchi K.;Murgas F.;Palle E.;Narita N.;Fukui A.;Hirano T.;et al.
背景美国宇航局太空望远镜 TESS 目前正在执行全天空搜索新凌日行星的扩展任务。在 TESS 预计将发射的数千个候选行星中，围绕 M 型矮星运行的凌日行星是特别有趣的目标，因为它们提供了通过透射光谱来表征其大气层的绝佳机会。目标我们的目标是验证和表征围绕附近 M 型矮星运行的新的亚海王星大小的候选行星 TOI-2136.01（d= 33.36 ± 0.02pc，Teff= 3373 ± 108） K），轨道周期为7.852天。方法我们使用TESS数据、地面多色光度测量以及斯巴鲁望远镜上的红外多普勒（IRD）仪器的径向速度测量来验证TOI-2136.01的行星性质，并估计恒星和行星参数。我们还进行了高分辨率透射光谱来寻找其大气中的氦。结果我们确认TOI-2136.01（现命名为TOI-2136b）是一颗真正的行星，行星半径为Rp= 2.20 ± 0.07R⊕，质量为Mp= 4.7−2.6+3.1M⊕。我们还搜索氦 10830 Å 吸收线，并以 95% 的置信度将等效宽度设置为 <7.8 mÅ 的上限，将吸收信号设置为 <1.44%。 结论 TOI-2136b 是一颗凌日附近明亮恒星（J= 10.8 星等）的亚海王星，是一颗潜在的海藻行星，是一类新的宜居行星，其下方有大片海洋。富含氢气的大气，使其成为大气研究的绝佳目标，以了解小行星的形成、演化和宜居性。
ContextThe NASA space telescope TESS is currently in the extended mission of its all-sky search for new transiting planets. Of the thousands of candidates that TESS is expected to deliver, transiting planets orbiting nearby M dwarfs are particularly interesting targets since they provide a great opportunity to characterize their atmospheres by transmission spectroscopy.AimsWe aim to validate and characterize the new sub-Neptune-sized planet candidate TOI-2136.01 orbiting a nearby M dwarf (d= 33.36 ± 0.02pc,Teff= 3373 ± 108 K) with an orbital period of 7.852 days.MethodsWe use TESS data, ground-based multicolor photometry, and radial velocity measurements with the InfraRed Doppler (IRD) instrument on the Subaru Telescope to validate the planetary nature of TOI-2136.01, and estimate the stellar and planetary parameters. We also conduct high-resolution transmission spectroscopy to search for helium in its atmosphere.ResultsWe confirm that TOI-2136.01 (now named TOI-2136b) is a bona fide planet with a planetary radius ofRp= 2.20 ± 0.07R⊕and a mass ofMp= 4.7−2.6+3.1M⊕. We also search for helium 10830 Å absorption lines and place an upper limit on the equivalent width of <7.8 mÅ and on the absorption signal of <1.44% with 95% confidence.ConclusionsTOI-2136b is a sub-Neptune transiting a nearby and bright star (J= 10.8 mag), and is a potentially hycean planet, which is a new class of habitable planets with large oceans under a H2-rich atmosphere, making it an excellent target for atmospheric studies to understand the formation, evolution, and habitability of the small planets.