Year: 2026
Type: article
Abstract: Theory predicts that a planet with a sufficiently strong magnetic field orbiting close to its host star could induce star-planet magnetic interactions. This is potentially observable as an optical or radio stellar activity signal synchronized with the planet's orbital period. We analyzed 18 years of high-resolution optical spectroscopy of GJ 436, a low-mass star orbited by a Neptune-sized exoplanet on a polar eccentric orbit. Stellar activity indicators show enhancements at a period corresponding to the exoplanet orbit, modulated by stellar rotation, and the star's 8-year magnetic cycle. We interpret this as a signal of star-planet magnetic interaction. Using a geometric model, we reproduced these periods if GJ 436 b has a magnetic field strength of 6 to 110 gauss.
Source: Science
Institutions: Consejo Superior de Investigaciones Científicas, Instituto de Astrofísica de Andalucía, University of Chicago, Osservatorio Astrofisico di Catania, National Institute for Astrophysics, Tel Aviv University, Instituto Nacional de Técnica Aeroespacial, Centro de Astrobiología, Thüringer Landessternwarte Tautenburg, Tennessee State University, Universitat Autònoma de Barcelona, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Universidad de La Laguna, Instituto de Astrofísica de Canarias, European University Cyprus, Heidelberg University, University of Göttingen, Institute of Applied Computing & Community Code, Universitat de les Illes Balears
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7165955868