Measuring the magnetic fields in the chromospheres of low-mass stars
Magnetic fields in the upper atmospheres of solar-like stars are believed to provide an enormous amount of energy to power the hot coronae and drive large-scale eruptions that could impact the habitability of planetary systems around these stars. However, these magnetic fields have never been routinely measured on stars beyond the solar system. Through decade-long spectropolarimetric observations, we have now achieved the measurements of magnetic fields in the lower and middle chromospheres of three M-dwarfs. Our results indicate that the line-of-sight component of the chromospheric magnetic fields can reach up to hundreds of Gauss, whose sign frequently opposes that of the photospheric field. The measurements highlight the magnetic field complexity and the variation with height close to the surface of these M-dwarfs. They provide critical constraints on the energy budget responsible for heating and eruptions of stellar upper atmospheres, and enable assessments of how stellar magnetic activity may affect exoplanet environments.
Authors
- Xueying Hu (ORCID: https://orcid.org/0009-0001-9789-3858)
- Hui Tian (ORCID: https://orcid.org/0000-0002-1369-1758)
- A. López Ariste (ORCID: https://orcid.org/0000-0002-1097-8307)
- Hongpeng Lu (ORCID: https://orcid.org/0000-0001-8037-5256)
- Xiao-Yu Ma (ORCID: https://orcid.org/0000-0002-7468-3612)
- Weikai Zong (ORCID: https://orcid.org/0000-0002-7660-9803)
- J.‐F. Donati (ORCID: https://orcid.org/0000-0001-5541-2887)
- J. Morin (ORCID: https://orcid.org/0000-0002-4996-6901)
- Tianqi Cang (ORCID: https://orcid.org/0000-0003-3816-7335)
- S. Bellotti (ORCID: https://orcid.org/0000-0002-2558-6920)
- Jian-Ning Fu (ORCID: https://orcid.org/0000-0001-8241-1740)
- P. Petit (ORCID: https://orcid.org/0000-0001-7624-9222)
- Keyu Xing (ORCID: https://orcid.org/0009-0003-8858-2833)
- Hao Li (ORCID: https://orcid.org/0000-0001-5612-4457)
Institutions
- Leiden University (NL)
- Centre National de la Recherche Scientifique (FR)
- Guizhou University (CN)
- Université de Montpellier (FR)
- Peking University (CN)
- Beijing Normal University (CN)
- Beijing Planetarium (CN)
- Laboratoire Univers et Particules de Montpellier (FR)
- National Space Science Center (CN)
- Institut de Recherche en Astrophysique et Planétologie (FR)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-11-29
- DOI
- https://doi.org/10.1038/s41467-025-66624-9
- Citations
- 1
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- China Postdoctoral Science Foundation
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek
- Horizon 2020 Framework Programme