Investigating the rotational phase of stellar flares on M dwarfs using K2 short cadence data
Year: 2018
Type: article
Abstract: We present an analysis of K2 short cadence data of 34 M dwarfs which have spectral types in the range M0–L1. Of these stars, 31 showed flares with a duration between ∼10 and 90min. Using distances obtained from Gaia DR2 parallaxes, we determined the energy of the flares to be in the range ∼1.2 × 1029–6 × 1034 erg. In agreement with previous studies we find rapidly rotating stars tend to show more flares, with evidence for a decline in activity in stars with rotation periods longer than ∼10 d. The rotational modulation seen in M dwarf stars is widely considered to result from a starspot which rotates in and out of view. Flux minimum is therefore the rotation phase where we view the main starspot close to the stellar disc centre. Surprisingly, having determined the rotational phase of each flare in our study we find none show any preference for rotational phase. We outline three scenarios which could account for this unexpected finding. The relationship between rotation phase and flare rate will be explored further using data from wide surveys such as NGTS and TESS.
Authors: L Doyle, G Ramsay, J G Doyle, K Wu, E Scullion
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Johns Hopkins University, Space Telescope Science Institute, European Space Agency, Queen's University Belfast, Durham University, National Central University, Eötvös Loránd Tudományegyetem, Max-Planck-Institut für Astronomie, Smithsonian Astrophysical Observatory, Science Mission Directorate, Science and Technology Facilities Council, Planetary Science Division, Los Alamos National Laboratory
Awards: MSSL/UCL Astrophysics Consolidated Grant 2016-2019, G4474636675, Characterising the properties of Solar and Stellar Flares, G618131832, A NEO SEARCH PROGRAM USING THE PAN-STARRS PS1 TELESCOPETHE GOAL OF THE PROPOSED RESEARCH IS TO USE T, G7187964967, Pan-STARRS1: Operations; Public Data Release; Education and Outreach, G833430883
OpenAlex ID: W2883633260