Mercury's Eccentric Orbit as a Driver of Significant “Seasonal” Change in Upstream Solar Wind Forcing
Year: 2026
Type: article
Abstract: Mercury experiences the most intense and variable solar wind (SW) conditions in the solar system due to its close, eccentric orbit about the Sun. In addition to variation driven by coronal source and solar cycle, the SW arriving at Mercury varies periodically as the planet's heliocentric distance changes by over 50% per orbit. We use 30 years of SW measurements near Earth and scale them to Mercury's orbital distance to determine the importance of this “seasonal” change in the SW. We find the seasonal change to be substantial, systematic, and significant, and that it dominates over other sources of variability (e.g., fast vs. slow SW) and even exceeds the relative change at Earth from ICMEs compared to the ambient SW. As a result, Mercury's magnetosphere is expected to exhibit substantial seasonal effects.
Source: Geophysical Research Letters
DOI: 10.1029/2026gl123323
Authors: Ryan M. Dewey, Caitriona Mary Jackman, Mathias Rojo, Lina Z. Hadid, Beatriz Sánchez‐Cano, Charles F. Bowers, Jim M. Raines, Susan T. Lepri, Stefano Livi, Jesse T. Coburn, Sae Aizawa, Yeimy J. Rivera, Weijie Sun, Jiutong Zhao, James A. Slavin, Daniel Heyner, Daragh M. Hollman, Alexander D. Shane
Institutions: University of Michigan, Dublin Institute For Advanced Studies, Centre National de la Recherche Scientifique, Institut de Recherche en Astrophysique et Planétologie, École Polytechnique, Université Paris-Saclay, Observatoire de Paris, Sorbonne Université, Institut Polytechnique de Paris, Laboratoire de Physique des Plasmas, University of Leicester, Southwest Research Institute, Smithsonian Astrophysical Observatory, Center for Astrophysics Harvard & Smithsonian, Space Sciences Laboratory, University of California, Berkeley, Technische Universität Braunschweig, University of Colorado Boulder
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
OpenAlex ID: W7165152605