Detailed cool star flare morphology with CHEOPS and TESS
| Autor: | Bruno, G., Pagano, I., Scandariato, G., Florén, H. -G., Brandeker, A., Olofsson, G., Maxted, P. F. L., Fortier, A., Sousa, S. G., Sulis, S., Van Grootel, V., Garai, Z., Boldog, A., Kriskovics, L., Szabó, M. Gy., Gandolfi, D., Alibert, Y., Alonso, R., Bárczy, T., Navascues, D. Barrado, Barros, S. C. C., Baumjohann, W., Beck, M., Beck, T., Benz, W., Billot, N., Borsato, L., Broeg, C., Cameron, A. Collier, Csizmadia, Sz., Cubillos, P. E., Davies, M. B., Deleuil, M., Deline, A., Delrez, L., Demangeon, O. D. S., Demory, B. -O., Ehrenreich, D., Erikson, A., Farinato, J., Fossati, L., Fridlund, M., Gillon, M., Güdel, M., Günther, M. N., Heitzmann, A., Helling, Ch., Hoyer, S., Isaak, K. G., Kiss, L., Lam, K. W. F., Laskar, J., Etangs, A. Lecavelier des, Lendl, M., Magrin, D., Mordasini, C., Nascimbeni, V., Ottensamer, R., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Ratti, F., Rauer, H., Ribas, I., Santos, N. C., Sarajlic, M., Ségransan, D., Simon, A. E., Singh, V., Smith, A. M. S., Stalport, M., Thomas, N., Udry, S., Ulmer, B., Venturini, J., Villaver, E., Walton, N. A., Wilson, T. G. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | 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 UV 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. We developed dedicated software for this purpose. Results. Multi-peak flares represent a significant percentage ($\gtrsim 30$\%) 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-peak 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 quasi-periodic pulsations 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 will help in this respect. Comment: 28 pages, 25 figures, 4 tables, to be published in Astronomy & Astrophysics |
| Databáze: | arXiv |
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