Constraining an exoplanet’s magnetic field using star-planet interactions
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.
Article Details
Journal Info
Science
American Association for the Advancement of Science
Authors (20)
D. Revilla
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
P. J. Amado
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
R. Luque
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
P. Schöfer
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
A. F. Lanza
Osservatorio Astrofisico di Catania, Istituto Nazionale di Astrofisica, Catania, Italy.
A. Binnenfeld
Porter School of the Environment and Earth Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.
J. A. Caballero
A. P. Hatzes
Thüringer Landessternwarte Tautenburg, Tautenburg, Germany.
G. W. Henry
Tennessee State University, Nashville, TN, USA.
S. V. Jeffers
Thüringer Landessternwarte Tautenburg, Tautenburg, Germany.
S. Kaur
Institut d’Estudis Espacials de Catalunya, Castelldefels, Barcelona, Spain.
E. Pallé
Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain.
L. Peña-Moñino
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
M. Pérez-Torres
Instituto de Astrofísica de Andalucía - Consejo Superior de Investigaciones Científicas, Granada, Spain.
A. Quirrenbach
Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Heidelberg, Germany.
A. Reiners
Institut für Astrophysik und Geophysik, Georg-August-Universität, Göttingen, Germany.
I. Ribas
Institut d’Estudis Espacials de Catalunya, Castelldefels, Barcelona, Spain.
D. Viganò
Institut d’Estudis Espacials de Catalunya, Castelldefels, Barcelona, Spain.
M. R. Zapatero-Osorio
Centro de Astrobiología, Instituto Nacional de Técnica Aeroespacial - Consejo Superior de Investigaciones Científicas, Centro Europeo de Astronomía Espacial Campus, Villanueva de la Cañada, Madrid, Spain.
S. Zucker
Porter School of the Environment and Earth Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.