TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399
TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399
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DOI：
10.3847/1538-3881/ac0432
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
J. Burt;D. Dragomir;P. Mollière;A. Youngblood;A. G. Muñoz;J. McCann;L. Kreidberg;Chelsea X. Huang-Chelsea
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文献类型：
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作者：
J. Burt;D. Dragomir;P. Mollière;A. Youngblood;A. G. Muñoz;J. McCann;L. Kreidberg;Chelsea X. Huang-Chelsea
我们报告发现了一个过境，温带，海王星大小的系外行星轨道附近（d = 27.5 pc），M3 V星星TOI-1231（NLTT 24399，L 248-27，2 MASS J10265947-5228099）。这颗行星是利用凌日系外行星勘测卫星的光度数据探测到的，随后又利用拉斯坎布雷斯天文台和南极洲凌日系外行星搜索计划进行了观测。结合测光数据集，我们发现这颗新发现的行星的半径为3.65−0.15+0.16R <$，轨道周期为24.246天。麦哲伦粘土望远镜上的行星光谱仪获得的径向速度测量证实了行星的存在，并导致质量测量为15.5 ± 3.3 M <$。TOI-1231 B的平衡温度仅为330 K，是迄今为止可用于大气研究的最冷的小行星之一，其宿主星星明亮的近红外亮度（J = 8.88，KS = 8.07）使其成为哈勃太空望远镜和詹姆斯·韦伯B太空望远镜的令人兴奋的目标。未来的大气观测将通过与K2-18 B的比较，在250-350 K温度范围内进行首次比较行星学研究。此外，TOI-1231的高系统径向速度（70.5 km s−1）可能允许通过多普勒探测逃离行星的低速氢原子，使H i Lyα恒星发射远离地冠和星际介质吸收特征。
We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby (d = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the Antarctica Search for Transiting ExoPlanets program. Combining the photometric data sets, we find that the newly discovered planet has a radius of 3.65−0.15+0.16R⊕ and an orbital period of 24.246 days. Radial velocity measurements obtained with the Planet Finder Spectrograph on the Magellan Clay telescope confirm the existence of the planet and lead to a mass measurement of 15.5 ± 3.3 M ⊕. With an equilibrium temperature of just 330 K, TOI-1231 b is one of the coolest small planets accessible for atmospheric studies thus far, and its host star’s bright near-infrared brightness (J = 8.88, K s = 8.07) makes it an exciting target for the Hubble Space Telescope and the James Webb Space Telescope. Future atmospheric observations would enable the first comparative planetology efforts in the 250–350 K temperature regime via comparisons with K2-18 b. Furthermore, TOI-1231's high systemic radial velocity (70.5 km s−1) may allow for the detection of low-velocity hydrogen atoms escaping the planet by Doppler, shifting the H i Lyα stellar emission away from the geocoronal and interstellar medium absorption features.