Ilin Ekaterina, Vedantham Harish K, Poppenhäger Katja, Bloot Sanne, Callingham Joseph R, Brandeker Alexis, Chakraborty Hritam
Netherlands Institute for Radio Astronomy (ASTRON), Dwingeloo, The Netherlands.
Leibniz-Institut für Astrophysik Potsdam (AIP), Potsdam, Germany.
Nature. 2025 Jul;643(8072):645-648. doi: 10.1038/s41586-025-09236-z. Epub 2025 Jul 2.
In the past decade, hundreds of exoplanets have been discovered in extremely short orbits below 10 days. Unlike in the Solar System, planets in these systems orbit their host stars close enough to disturb the stellar magnetic field lines. The interaction can enhance the magnetic activity of the star, such as its chromospheric and radio emission or flaring. So far, the search for magnetic star-planet interactions has remained inconclusive. Here we report the detection of planet-induced flares on HIP 67522, a 17 million-year-old G dwarf star with two known close-in planets. Combining space-borne photometry from the Transiting Exoplanet Survey Satellite and dedicated Characterising Exoplanets Telescope observations over 5 years, we find that the 15 flares in HIP 67522 cluster near the transit phase of the innermost planet, indicating persistent magnetic star-planet interaction in the system. The stability of interaction implies that the innermost planet is continuously self-inflicting a six times higher flare rate than it would experience without interaction. The subsequent flux of energetic radiation and particles bombarding HIP 67522 b may explain the remarkably extended atmosphere of the planet, recently detected with the James Webb Space Telescope. HIP 67522 is, therefore, an archetype to understand the impact of magnetic star-planet interaction on the atmospheres of nascent exoplanets.
在过去十年中，已经发现了数百颗处于极短轨道（周期小于10天）的系外行星。与太阳系不同，这些系统中的行星绕其主恒星运行的距离足够近，足以扰乱恒星的磁场线。这种相互作用会增强恒星的磁活动，比如其色球层发射、射电发射或耀斑。到目前为止，对磁星-行星相互作用的搜寻尚无定论。在此，我们报告在HIP 67522上探测到了行星诱发的耀斑，这是一颗有着1700万年历史的G矮星，已知有两颗近距离行星。结合凌日系外行星勘测卫星的太空光度测量数据以及专用的系外行星特征望远镜长达5年的观测结果，我们发现HIP 67522中的15次耀斑聚集在最内侧行星的凌星阶段附近，这表明该系统中存在持续的磁星-行星相互作用。这种相互作用的稳定性意味着，最内侧行星自身造成的耀斑发生率比没有相互作用时高出六倍。随后高能辐射和粒子轰击HIP 67522 b，这或许可以解释最近用詹姆斯·韦布空间望远镜探测到的该行星显著扩展的大气层。因此，HIP 67522是理解磁星-行星相互作用对新生系外行星大气层影响的一个典型例子。
