致密多行星系统TOI-789的表征：三颗类地行星的验证、动力学表征及第四颗温带候选体的探测
Characterization of the Compact Multi-planet System TOI-789: Validation of Three Terrestrial Planets, Dynamical Characterization, and Detection of a Fourth Temperate Candidate
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中文总结 AI 辅助
本研究验证了M3矮星TOI-789周围三颗类地行星并发现第四颗温带候选体，通过动力学分析揭示其近共振、低偏心率稳定特征，为比较行星学提供了重要样本。
中文摘要 AI 辅助
我们展示了TOI-789（TIC 300710077）的验证与动力学表征，这是一个围绕距离43 pc处M3矮星的致密多行星系统。利用约7年的TESS测光数据（42个扇区）、公共地面后续观测（LCOGT、MEarth）以及高分辨率成像（Gemini/Zorro、SOAR），我们通过TRICERATOPS统计验证了三颗类地行星：TOI-789 b（Rp = 1.18 Rearth，P = 5.45天）、c（1.15 Rearth，8.04天）和d（1.40 Rearth，12.97天），在利用目标地面测光排除邻近源后，其假阳性概率和邻近假阳性概率均低于验证阈值。通过迭代的Transit Least Squares搜索，我们识别出第四颗此前未编目的行星候选体（P = 19.74天，Rp ~ 0.88 Rearth），它是系统中最外侧且温度最温和的成员（S = 1.71 Searth，Teq ~ 292 K）；其低信噪比阻碍了正式验证，因此我们将其报告为待确认的候选体。动力学分析（SPOCK和N体积分）表明该系统处于动力学冷、近共振状态，仅对低偏心率（e < 0.05）稳定，偏心率而非质量限制了稳定性；纳入第四颗候选体进一步收紧了这一约束。这四颗天体跨越了金星带中的地球-金星过渡区，其中两颗已验证行星在平衡温度准则下落入温带区域，使该系统成为以已确认行星为锚点的比较行星学潜在实验室。低TSM（~3-5）和中等的主星亮度使大气表征超出当前能力范围。TOI-789代表了M矮星周围致密类地行星系统中数量占优的一类，其表征受限于主星亮度，而动力学表征为此提供了补充途径。
英文摘要
We present the validation and dynamical characterization of TOI-789 (TIC 300710077), a compact multi-planet system around an M3 dwarf at 43 pc. Using ~7 yr of TESS photometry (42 sectors), public ground-based follow-up (LCOGT, MEarth), and high-resolution imaging (Gemini/Zorro, SOAR), we statistically validate three terrestrial planets with TRICERATOPS: TOI-789 b (Rp = 1.18 Rearth, P = 5.45 d), c (1.15 Rearth, 8.04 d), and d (1.40 Rearth, 12.97 d), with false-positive and nearby-false-positive probabilities below the validation thresholds once resolved neighbours are excluded using the on-target ground-based photometry. Through an iterative Transit Least Squares search we identify a fourth, previously uncatalogued planet candidate (P = 19.74 d, Rp ~ 0.88 Rearth), the outermost and most temperate member (S = 1.71 Searth, Teq ~ 292 K); its low signal-to-noise ratio precludes formal validation, so we report it as a candidate pending confirmation. A dynamical analysis (SPOCK and N-body integrations) indicates a dynamically cold, near-resonant system, stable only for low eccentricities (e < 0.05), eccentricity rather than mass limiting stability; including the fourth candidate tightens this further. The four objects span the Earth-Venus transition across the Venus zone, two validated planets falling in the temperate regime under the equilibrium-temperature criterion, making the system a potential comparative-planetology laboratory anchored on confirmed planets. The low TSM (~3-5) and moderate host brightness place atmospheric characterization beyond reach. TOI-789 exemplifies the numerically dominant population of compact terrestrial-planet systems around M dwarfs whose characterization is limited by host brightness, for which dynamical characterization offers a complementary route.
