TOI-6981 b：位于水冰线附近的凌星亚海王星
TOI-6981 b: a transiting sub-Neptune at the water ice line
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中文总结 AI 辅助
本文发现并验证了一颗位于水冰线附近的寒冷亚海王星TOI-6981 b，其轨道周期60.8天，温度约170 K，且透射光谱度量值较高，适合JWST大气研究，有望成为冷化学和行星形成研究的关键目标。
中文摘要 AI 辅助
我们介绍了TOI-6981 b，这是一颗寒冷的（假设地球反照率，平衡温度Teq=170.0±4.5 K）亚海王星（半径Rb=2.40±0.10 R⊕），绕其M4型宿主恒星（恒星半径R*=0.304±0.012 R☉，恒星质量M*=0.296±0.026 M☉，有效温度Teff=3215±58 K）运行，轨道周期为60.8天，属于SPECULOOS TEMPOS计划的一部分。我们利用地面后续测光、统计验证和高分辨率光谱学确认了TOI-6981 b的行星性质。在如此寒冷的温度下，TOI-6981 b大致位于水冰线（约170 K）附近。鉴于其轨道周期和高透射光谱度量值（TSM=51±9），它是稀疏分布的冷行星区域中少数适合用JWST进行大气研究的行星之一。因此，TOI-6981 b可能成为冷化学研究、海神世界假说检验以及类比太阳系冰巨行星的重要基准。此外，鉴于其当前轨道，它可能为水冰线处或更远处的行星形成与迁移提供见解。
英文摘要
We present TOI-6981 b, a cold (Teq= 170.0 +/-4.5 K, assuming an Earth-like albedo) sub-Neptune (Rb=2.40+/-0.10 R_oplus) on a 60.8 day orbit around around its M4-type host star (R*=0.304 +/- 0.012 R_odot, M*=0.296 +/- 0.026 M_odot, Teff = 3215+/-58K), part of the SPECULOOS TEMPOS program. We validate the planetary nature of TOI-6981 b using ground-based follow-up photometry, statistical validation and high-resolution spectroscopy. At such cold temperatures, TOI-6981 b sits roughly at the location of the water ice line (approx 170 K). Given its orbital period and high transmission spectroscopy metric (TSM=51 +/- 9), it is one of the only planets in the sparsely populated cold planet regime amenable for atmospheric studies with JWST. Therefore, TOI-6981 b could. possibly become a crucial benchmark in cold chemistry studies, tests of Hycean world hypotheses, and drawling parallels to the Solar System's ice giants. Additionally, given its current orbit, it may provide insight into planetary formation and migration at or beyond the water ice line.
