首次利用哈勃望远镜探测到岩石系外行星的次食：5.4小时行星TOI-2431 b
The First Hubble Detection of a Secondary Eclipse from a Rocky Exoplanet: the 5.4-hour planet TOI-2431 b
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中文总结 AI 辅助
利用HST/WFC3 G141和TESS数据首次探测到岩石系外行星TOI-2431 b的次食，约束其热辐射与反照率，确立其为研究熔岩世界的基准目标。
中文摘要 AI 辅助
我们展示了利用HST/WFC3 G141对超短周期岩石行星TOI-2431 b进行的相位曲线观测，并在近红外波段探测到了其次食。结合TESS光学波段的食信号，这些测量约束了该行星的昼面亮温、反射光贡献、反照率以及热量再分布。我们在TESS和HST/WFC3 G141的光学及近红外波段探测到了食信号，行星与恒星的通量比分别为37±10 ppm和69(+14/-13) ppm。假设反射光可忽略，联合TESS+HST拟合得到的亮温T_b,joint=2524(+77/-84) K，亮温比R_joint=T_b,joint/T_p,max=0.980(+0.032/-0.034)，与零反照率、无再分布极限T_p,max=2574(+36/-35) K一致。HST相位曲线与零夜面辐射及无可测量的热点偏移一致，表明昼夜热量分布效率低下。在这种热主导的解释下，TOI-2431 b处于零反照率、无再分布极限，与之前观测到的熔岩世界形成对比。然而，在光学和近红外波段，热辐射与反射光存在简并。对于几何反照率A_g=0.1，反射光在每个波段将贡献约11 ppm，使温度降至T_b,joint(A_g=0.1)=2407(+91/-102) K。需要更长波长的观测来分离热成分。计划中的JWST/MIRI LRS观测预计将大幅减少这种简并，并为热量再分布和可能的硅酸盐大气光谱特征提供更直接的约束。这标志着首次利用HST探测到岩石系外行星的次食，并使TOI-2431 b成为研究熔岩世界性质的基准目标。
英文摘要
We present an HST/WFC3 G141 phase-curve observation of the ultra-short-period rocky planet TOI-2431 b and detect its secondary eclipse in the near infrared. Combined with the TESS optical eclipse, these measurements constrain the planet's dayside brightness temperature, reflected light contribution, albedo, and heat redistribution. We detect the eclipse in the optical and near infrared wavelengths of TESS and HST/WFC3 G141, with a planet-to-star flux ratio of 37+/-10 ppm and 69(+14/-13) ppm, respectively. Assuming negligible reflected light, the joint TESS+HST fit yields a brightness temperature T_b,joint=2524(+77/-84) K and a brightness temperature ratio of R_joint=T_b,joint/T_p,max=0.980(+0.032/-0.034) consistent with the zero-albedo, no-redistribution limit T_p,max=2574(+36/-35) K. The HST phase curve is consistent with zero nightside emission and no measurable hotspot offset, consistent with inefficient day-night heat distribution. Under this thermal-dominated interpretation, TOI-2431 b lies at the zero-albedo, no-redistribution limit and contrasts with previously observed lava worlds. At optical and near-infrared wavelengths, however, thermal emission is degenerate with reflected light. For a geometric albedo of A_g=0.1, reflected light would contribute approximately 11 ppm in each bandpass, reducing the temperature to T_b,joint(A_g=0.1)=2407(+91/-102) K. Longer-wavelength observations are required to isolate the thermal component. Planned JWST/MIRI LRS observations are expected to substantially reduce this degeneracy and provide more direct constraints on heat redistribution and possible silicate-atmosphere spectral features. This marks the first secondary eclipse detection of a rocky exoplanet using HST and establishes TOI-2431 b as a benchmark target for studying properties of lava worlds.
发表机构
- Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森天体物理中心）
- SRON, Space Research Organisation Netherlands（荷兰空间研究组织）
- Leiden Observatory（莱顿天文台）
- McGill University（麦吉尔大学）
- Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）
- Space Telescope Science Institute（太空望远镜科学研究所）
- Waterloo Centre for Astrophysics and Department of Physics and Astronomy, University of Waterloo（滑铁卢大学天体物理中心及物理与天文学系）
机构由 AI 辅助整理，请以论文原文为准。
