Detailed cool star flare morphology with CHEOPS and TESS

Autor(en): G. Bruno, I. Pagano, G. Scandariato, H. G. Florén, A. Brandeker, G. Olofsson, P. F.L. Maxted, A. Fortier, S. G. Sousa, S. Sulis, V. Van Grootel, Z. Garai, A. Boldog, L. Kriskovics, Gy M. Szabó, D. Gandolfi, Y. Alibert, R. Alonso, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, L. Borsato, C. Broeg, A. Collier Cameron, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D.S. Demangeon, B. O. Demory, D. Ehrenreich, A. Erikson, J. Farinato, L. Fossati, M. Fridlund, M. Gillon, M. Güdel, M. N. Günther, A. Heitzmann, Ch Helling, S. Hoyer, K. G. Isaak, L. L. Kiss, K. W.F. Lam, J. Laskar, A. Lecavelier des Etangs, M. Lendl, D. Magrin, C. Mordasini, V. Nascimbeni, R. Ottensamer, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, N. C. Santos, M. Sarajlic, D. Ségransan, A. E. Simon, V. Singh, A. M.S. Smith, M. Stalport, N. Thomas, S. Udry, B. Ulmer, J. Venturini, E. Villaver, N. A. Walton, T. G. Wilson
Abstrakt: Context. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and ultraviolet emission, their study is particularly relevant to estimate the amount of high-energy irradiation onto the atmospheres of exoplanets, especially those in their stars’ habitable zone. Aims. We used the high-cadence, high-photometric capabilities of the CHEOPS and TESS space telescopes to study the detailed morphology of white-light flares occurring in a sample of 130 late-K and M stars, and compared our findings with results obtained at a lower cadence. Methods. We employed dedicated software for the reduction of 3 s cadence CHEOPS data, and adopted the 20 s cadence TESS data reduced by their official processing pipeline. We developed an algorithm to separate multi-peak flare profiles into their components, in order to contrast them to those of single-peak, classical flares. We also exploited this tool to estimate amplitudes and periodicities in a small sample of quasi-periodic pulsation (QPP) candidates. Results. Complex flares represent a significant percentage (≳30%) of the detected outburst events. Our findings suggest that high-impulse flares are more frequent than suspected from lower-cadence data, so that the most impactful flux levels that hit close-in exoplanets might be more time-limited than expected. We found significant differences in the duration distributions of single and complex flare components, but not in their peak luminosity. A statistical analysis of the flare parameter distributions provides marginal support for their description with a log-normal instead of a power-law function, leaving the door open to several flare formation scenarios. We tentatively confirmed previous results about QPPs in high-cadence photometry, report the possible detection of a pre-flare dip, and did not find hints of photometric variability due to an undetected flare background. Conclusions. The high-cadence study of stellar hosts might be crucial to evaluate the impact of their flares on close-in exoplanets, as their impulsive phase emission might otherwise be incorrectly estimated. Future telescopes such as PLATO and Ariel, thanks to their high-cadence capability, will help in this respect. As the details of flare profiles and of the shape of their parameter distributions are made more accessible by continuing to increase the instrument precision and time resolution, the models used to interpret them and their role in star-planet interactions might need to be updated constantly.
Organisation(en): Institut für Astrophysik
Externe Organisation(en): INAF-Osservatorio Astrofisico di Catania, Stockholm University, Keele University, Universität Bern, Universidade do Porto, Aix-Marseille Université, Université de Liège, HUN-REN Magyar Kutatási Hálózat, Eötvös Loránd University Budapest, Slovenian Academy of Sciences and Arts, MTA Társadalomtudományi Kutatóközpont, Magyar Tudományos Akadémia, Università degli Studi di Torino, Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, Admatis, European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), Universität Genf, INAF - Osservatorio Astronomico di Padova, University of St. Andrews, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), INAF-Osservatorio Astrofisico di Torino, Lund University, Katholieke Universiteit Leuven, Leiden University, Chalmers University of Technology, European Space Research & Technology Centre (ESA/ESTEC), Technische Universität Graz, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Università degli Studi di Padova, University of Warwick, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Freie Universität Berlin (FU), Spanish National Research Council (CSIC), Institut d'Estudis Espacials de Catalunya (IEEC)
Journal: Astronomy and Astrophysics
Band: 686
Anzahl der Seiten: 27
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202348951
Publikationsdatum: 06-2024
Peer-reviewed: Ja
ÖFOS 2012: 103003 Astronomie, 103004 Astrophysik, 103038 Weltraumforschung
Schlagwörter
ASJC Scopus Sachgebiete: Astronomy and Astrophysics, Space and Planetary Science
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/2f99ddac-336d-496a-9f7f-01626a87f213

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