AU Mic b 多变面貌：由 CHEOPS 与 TESS 观测到的恒星黑子、自旋-轨道通约及凌星时刻变化
地球与行星天体物理
2021-11-17 v1 太阳与恒星天体物理
摘要
AU Mic 是一个年轻的行星系统，具有显示行星形成迹象的已分辨碎屑盘，以及两颗靠近平运动共振的凌星温海王星。本文分析了由 CHaracterising ExOPlanet Satellite（CHEOPS）观测的 AU Mic b 的三次凌星，并补充了第 1 与第 27 区 Transiting Exoplanet Survey Satellite（TESS）测光，以及地面 All-Sky Automated Survey（ASAS）数据。AU Mic b 的精化轨道周期为 8.462995 \pm 0.000003 d，而恒星自转周期为 P_{rot}=4.8367 \pm 0.0006 d。两周期表明 7:4 自旋-轨道通约，精度达 0.1%。因此，所有凌星均观测于四个可能恒星中心经度之一的前方。第二次与第三次 CHEOPS 观测相隔四个轨道（及七次恒星自转）却看到相同复杂星斑图样，强有力地支持了这一结论。通过自助分析我们发现，耀斑与星斑使行星-恒星半径比的凌星参数精度降低达 10%，并使凌星时刻精度降低 3-4 分钟。尽管如此，被掩恒星黑子特征独立确认了振幅至少 4 分钟的凌星时刻变化（TTVs）的存在。我们发现外侧伴星 AU Mic c 可能引起所观测到的 TTVs。
引用
@article{arxiv.2108.02149,
title = {The changing face of AU Mic b: stellar spots, spin-orbit commensurability, and Transit Timing Variations as seen by CHEOPS and TESS},
author = {Gy. M. Szabó and D. Gandolfi and A. Brandeker and Sz. Csizmadia and Z. Garai and N. Billot and C. Broeg and D. Ehrenreich and A. Fortier and L. Fossati and S. Hoyer and L. Kiss and A. Lecavelier des Etangs and P. F. L. Maxted and I. Ribas and Y. Alibert and R. Alonso and G. Anglada Escudé and T. Bárczy and S. C. C. Barros and D. Barrado and W. Baumjohann and M. Beck and T. Beck and A. Bekkelien and X. Bonfils and W. Benz and L. Borsato and M-D. Busch and J. Cabrera and S. Charnoz and A. Collier Cameron and C. Corral Van Damme and M. B. Davies and L. Delrez and M. Deleuil and O. D. S. Demangeon and B. -O. Demory and A. Erikson and M. Fridlund and D. Futyan and A. García Muñoz and M. Gillon and M. Guedel and P. Guterman and K. Heng and K. G. Isaak and G. Lacedelli and J. Laskar and M. Lend and C. Lovis and A. Luntzer and D. Magrin and V. Nascimbeni and G. Olofsson and H. P. Osborn and R. Ottensamer and I. Pagano and E. Pallé and G. Peter and D. Piazza and G. Piotto and D. Pollacco and D. Queloz and R. Ragazzoni and N. Rando and H. Rauer and N. C. Santos and G. Scandariato and D. Ségransan and L. M. Serrano and D. Sicilia and A. E. Simon and A. M. S. Smith and S. G. Sousa and M. Steller and N. Thomas and S. Udry and V. Van Grootel and N. A. Walton and T. G. Wilson},
journal= {arXiv preprint arXiv:2108.02149},
year = {2021}
}
备注
16 pages, 11 figures, 7 tables; accepted by Astronomy and Astrophysics