Related papers: Stellar Superflares Observed Simultaneously with K…
Solar flares strongly affect the Sun's atmosphere as well as the Earth's environment. Quantifying the maximum possible energy of solar flares of the present-day Sun, if any, is thus a key question in heliophysics. The largest solar flares…
We present the results of an observational campaign which obtained high time cadence, high precision, simultaneous optical and IR photometric observations of three M dwarf flare stars for 47 hours. The campaign was designed to characterize…
We analyze new observations of superflares on G-stars discovered in the optical and near IR ranges with the Kepler mission. An evolution of solar-type activity is discussed. We give an estimate of the maximal total energy, $E_{tot} =…
Context. Quasi-periodic pulsations (QPPs) are time variations in the energy emission during a flare that are observed on both the Sun and other stars and thus have the potential to link the physics of solar and stellar flares. Aims. To…
Cool stars are known to produce flares probably as a result of magnetic reconnection in their outer atmospheres. We present simultaneous XMM-Newton optical V band and X-ray observations of the M8 dwarf LP412-31. During the observation a…
We report a NuSTAR observation of a solar microflare, SOL2015-09-01T04. Although it was too faint to be observed by the GOES X-ray Sensor, we estimate the event to be an A0.1 class flare in brightness. This microflare, with only 5 counts…
According to recent observations relative number of flare stars does not change very much from cool dwarfs to hot A stars. Flare energies are strongly correlated with stellar luminosity and radius. Whence it follows that the typical…
Context. X-ray flares are common phenomena in pre-main sequence stars. Their analysis gives insights into the physics at work in young stellar coronae. The Orion Nebula Cluster offers a unique opportunity to study large samples of young low…
We present light curves and flares from a seven day, multi-wavelength observational campaign of AU Mic, a young and active dM1e star with exoplanets and a debris disk. We report on 73 unique flares between the X-ray to optical data. We use…
We analyzed the occurrence rates of flares on stars of spectral types K, G, F, and A, observed by Kepler. We found that the histogram of occurrence frequencies of stellar flares is systematically shifted towards a high-energy tail for…
The magnetic field of the Sun drives a wide range of eruptive phenomena, from small-scale nanoflares to large flares and coronal mass ejections (CMEs). While direct observations of solar activity cover only the past few decades, indirect…
The light curves of solar-type stars present both periodic fluctuation and flare spikes. The gradual periodic fluctuation is interpreted as the rotational modulation of magnetic features on the stellar surface and is used to deduce magnetic…
We present a detailed analysis of a superflare on the active M dwarf star AD Leonis. The event presents a rare case of a stellar flare observed simultaneously in X-rays (with XMM-Newton) and in optical (with the Transiting Exoplanet Survey…
Solar flares often happen after a preflare / preheating phase, which is almost or entirely thermal. In contrast, there are the so-called early impulsive flares that do not show a (significant) preflare heating but instead often show the…
The Sun offers a convenient nearby laboratory to study the physical processes of particle acceleration and impulsive energy release in magnetized plasmas that occur throughout the universe, from planetary magnetospheres to black hole…
A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new…
Solar-type stars have been observed to flare at optical wavelengths to energies much higher than observed for the Sun. To date, no counterparts have been observed at longer wavelengths. We have searched the the VLA Sky Survey (VLASS) for…
Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated…
We investigate how the magnetic loop length of solar flares relates to the timing between their thermal and nonthermal emission signatures. Our study analyzes a sample of 96 C-, M-, and X-class flares observed between 2013 and 2015 with…
Using a recent census of flare stars from the Kepler survey, we have explored how flare activity evolves across stellar main sequence lifetimes. We utilize a sample of 347 stars with robust flare activity detections, and which have rotation…