J/A+A/708/A225ivo://CDS.VizieR/J/A+A/708/A225CDSSchmercz B.Seli B.Vida K.Kriskovics L.Gorgei A.Olah K.Regaly Zs.2026-05-04T07:43:19Z2026-04-08T13:01:28ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frlate-type-starsstellar-flaresphotometryvisible-astronomyStellar flares are sudden brightenings caused by magnetic reconnection and are frequently observed on late-type stars. High-cadence photometry of flares provides valuable insights into the mechanisms of these events, yet such observations remain scarce. We seek to explore the sub-second fine structure of stellar flares and assess the information content in high-speed photometry. New 0.3 s-cadence photometry from a six-year-long observing campaign of the active M-dwarf AD Leo is presented. We use time-frequency analysis to detect quasi-periodic pulsations in the decay phase of flares. We explore statistical measures of time series complexity of the detected flares to quantify the information gain achievable with high-cadence photometry. We detect 42 flares in 211 hours of observations. The flare frequency distribution is consistent with the previous literature. We find no quasi-periodic pulsations with periods below a few seconds, and identify two candidate signals with periods around 1 and 3 min. Using different measures of complexity on the binned flare light curves we confirm the advantages of high observing cadence. However, we also find a plateau up to a binning of ~4-5s for a few complex flares, suggesting that an exposure time of a few seconds is usually enough to retain most of the information carried by a single-filter observation. New photometric observations of AD Leo revealed sub-structures of flare light curves on the timescale of a few seconds, but we found no features on timescales below that.2026A&A...708A.225Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A225CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/637/A13 : AD Leo high resolution spectra (Muheki+, 2020)J/A+A/638/A5 : HD 285507 and AD Leo light and velocity curves (Carleo+, 2020)J/A+A/666/A143 : AD Leo RV and stellar activity indices (Kossakowski+, 2022)J/A+A/669/A118 : AD Leo spectral observations (Wollmann+, 2023)J/A+A/674/A110 : Gl 388 (AD Leo) RV curves (Carmona+, 2023)J/A+A/676/A56 : Large-scale magnetic field of AD Leo (Bellotti+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A225https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A225http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A225https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/708/A225https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/708/A225http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/708/A225GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap4.0234554602041486e-19 4.920466254354166e-19OpticaldefaultJ/A+A/708/A225/adleoFull observed light curve of AD LeorecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Datedtime.epochdoubleindexedBmagMagnitude in B Bandmagphot.mag;em.opt.Bfloat