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The connection between starspots and superflares: a case study of two stars

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Autor(es):
Araujo, Alexandre ; Valio, Adriana
Número total de Autores: 2
Tipo de documento: Artigo Científico
Fonte: Monthly Notices of the Royal Astronomical Society; v. 522, n. 1, p. 5-pg., 2023-06-01.
Resumo

How do the characteristics of starspots influence the triggering of stellar flares? Here, we investigate the activity of two K-type stars, similar in every way from mass to rotation periods and planetary systems. Both stars exhibit about a hundred spots; however, Kepler-411 produced 65 superflares, while Kepler-210 presented none. The spots of both stars were characterized using the planetary transit mapping technique, which yields the intensity, temperature, and radius of starspots. The average radius was (17 +/- 7) x10(3) and (58 +/- 23) x10(3) km, while the intensity ratio with respect to the photosphere was (0.35 +/- 0.24) and (0.64 +/- 0.15) I-c, and the temperature was (3800 +/- 700) and (4180 +/- 240) K for spots of Kepler-411 and Kepler-210, respectively. Therefore, spots on the star with no superflares, Kepler-210, are mostly larger, less dark, and warmer than those on the flaring star, Kepler-411. This may be an indication of magnetic fields with smaller magnitude and complexity of the spots on Kepler-210 when compared to those on Kepler-411. Thus, starspot area appears not to be the main culprit of superflares triggering. Perhaps the magnetic complexity of active regions is more important. (AU)

Processo FAPESP: 13/10559-5 - Investigação de fenômenos de altas energias e plasmas astrofísicos: teoria, simulações numéricas, observações e desenvolvimento de instrumentação para o Cherenkov Telescope Array (CTA)
Beneficiário:Elisabete Maria de Gouveia Dal Pino
Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais