AI 中文总结
研究对两颗年轻海王星大小行星TOI-560 b和TOI-5082 b进行自旋-轨道倾角测量，发现它们均为低倾角，支持约10亿年内的海王星大小行星普遍处于低倾角构型的结论。
AI 中文摘要
恒星倾角测量可直接探测行星系统动力学，但针对海王星大小行星的相关测量仍较为稀少，尤其在年轻行星领域。我们利用时间分辨的凯克行星搜寻仪（KPF）光谱学，结合TESS凌星测光的联合建模，对两颗年轻的海王星大小行星TOI-560 b和TOI-5082 b开展了罗斯特-麦克劳克林（Rossiter-McLaughlin）测量。我们测得TOI-560 b的天空投影倾角λ_b为-25±16°，TOI-5082 b的λ_b为19⁺¹⁷₋₁₃°。结合这些约束、恒星自转周期以及v sin i⋆的光谱估计值，我们分别得到95%置信上限ψ<69.7°和ψ<50.5°。因此，两个系统均符合低至中等真实倾角的特征，未发现强自旋-轨道错位的证据。TOI-560 b的年龄为480±190 Myr，TOI-5082 b的年龄为180±9 Myr（它很可能是CRIUS197星协的成员），这些系统处于盘后动力学过程（如长期相互作用）可能开始显现的关键演化阶段。尽管如此，两个系统仍符合低倾角的特征。在现有测量的年轻系统的更广泛背景下，这些结果支持了一种新兴的图景：年龄小于10亿年的海王星大小行星通常处于低倾角构型中。
英文摘要
Stellar obliquity measurements provide a direct probe of planetary system dynamics, but remain sparse for Neptune-size planets, particularly at young ages. We present Rossiter-McLaughlin measurements for two young Neptune-size planets, TOI-560 b and TOI-5082 b, using time-resolved Keck Planet Finder (KPF) spectroscopy and joint modeling with TESS transit photometry. We measure sky-projected obliquities of $λ_b = -25 \pm 16^\circ$ for TOI-560 b and $λ_b = 19^{+17}_{-13}{}^\circ$ for TOI-5082 b. Combining these constraints with stellar rotation periods and spectroscopic estimates of $v\sin i_\star$, we obtain 95% upper limits of $ψ< 69.7^\circ$ and $ψ< 50.5^\circ$, respectively. Both systems are therefore consistent with low-to-moderate true obliquities and show no evidence of strong spin-orbit misalignment. With ages of $480 \pm 190$ Myr for TOI-560 b and $180 \pm 9$ Myr for TOI-5082 b (a likely member of the CRIUS197 stellar association), the systems are in a key evolutionary phase when post-disk dynamical processes such as secular interactions may begin to manifest. Nevertheless, both systems remain consistent with low obliquity. In the broader context of young systems with existing measurements, these results support an emerging picture in which Neptune-size planets at $\lesssim 1$ Gyr are commonly found in low-obliquity configurations.
CommentsAccepted for publication in The Astronomical Journal
