From Starspots to Stellar Coronal Mass Ejections -- Revisiting Empirical Stellar Relations

Abstract

Upcoming missions, including the James Webb Space Telescope, will soon characterize the atmospheres of terrestrial-type exoplanets in habitable zones around cool K- and M-type stars searching for atmospheric biosignatures. Recent observations suggest that the ionizing radiation and particle environment from active cool planet hosts may be detrimental for exoplanetary habitability. Since no direct information on the radiation field is available, empirical relations between signatures of stellar activity, including the sizes and magnetic fields of starspots, are often used. Here, we revisit the empirical relation between the starspot size and the effective stellar temperature and evaluate its impact on estimates of stellar flare energies, coronal mass ejections, and fluxes of the associated stellar energetic particle events.

14 pages, 4 figures, 2 tables, accepted for publication in The Astrophysical Journal (07/11/2020)

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• The Gaia mission
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Cited by in corpus (11)

• Starspot mapping with adaptive parallel tempering. II. Application to TESS data for M-dwarf flare stars, AU Microscopii, YZ Canis Minoris, and EV Lacertae
• Untangling the Galaxy. IV. Empirical Constraints on Angular Momentum Evolution and Gyrochronology for Young Stars in the Field
• Stellar versus Galactic: The intensity of cosmic rays at the evolving Earth and young exoplanets around Sun-like stars
• A Machine Learning approach for correcting radial velocities using physical observables
• The energetic particle environment of a GJ 436 b-like planet
• Stellar Energetic Particle Transport in the Turbulent and CME-disrupted Stellar Wind of AU~Microscopii
• Solar and stellar flares: frequency, active regions and stellar dynamo
• Blackbody temperature of 200+ stellar flares observed with the CoRoT satellite
• Measuring the Temperature of Starspots from Multi-Filter Photometry
• Clarifying Physical Properties of Magnetic Fields in Sunspots
• Analysis of KIC 7023917 -- spotted low-mass ratio eclipsing binary with $\delta$ Scuti pulsations