Related papers: Giant white-light flares on fully convective stars…
White-light (WL) flares have been observed and studied more than a century since the first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the important facts in addressing the…
White-light flares are the flares with emissions visible in the optical continuum. They are thought to be rare and pose the most stringent requirements in energy transport and heating in the lower atmosphere. Here we present a nearly…
Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot…
Solar-type stars exhibit their highest levels of magnetic activity during their early convective pre-main sequence (PMS) phase of evolution. The most powerful PMS flares, super-flares and mega-flares, have peak X-ray luminosities of…
The giant flares produced by highly magnetized neutron stars, "magnetars," are the brightest sources of high energy radiation outside our solar system. Serendipitous observations with NASA's Rossi X-ray Timing Explorer (RXTE) of the two…
Observations of cool stars reveal dark spot-like features on their surfaces. Compared to sunspots, starspots can be bigger or cover a larger fraction of the stellar surface. While sunspots appear only at low latitudes, starspots are also…
Flare occurrence on the Sun is highly variable, exhibiting both short term variation due to the emergence and evolution of active regions, and long-term variation from the solar cycle. On solar-like stars, much larger stellar flares…
We analyze physical characteristics of late-type stars wherein the Kepler mission registered superflares. We use the revised stellar fundamental parameters, i.e. effective temperatures Teff and surface gravitational accelerations log g,…
23 giant flares from 13 active stars (eight RS CVn systems, one Algol system, three dMe stars and one YSO) were detected during the first two years of our all-sky X-ray monitoring with the gas propotional counters (GSC) of the Monitor of…
Hot luminous stars show a variety of phenomena in their photospheres and in their winds which still lack clear physical explanations at this time. Among these phenomena are non-thermal line broadening, line profile variability (LPVs),…
Solar flares are often accompanied by filament/prominence eruptions, sometimes leading to coronal mass ejections (CMEs). By analogy, we expect that stellar flares are also associated with stellar CMEs whose properties are essential to know…
In the settling accretion theory, which is applicable to quasi-spherical accreting slowly rotating magnetized neutron stars with X-ray luminosity $L_x\lesssim 4\times 10^{36}$~erg/s, bright X-ray flares ($\sim 10^{38}-10^{40}$~ergs)…
We describe observations of a white-light flare (SOL2011-02-24T07:35:00, M3.5) close to the limb of the Sun, from which we obtain estimates of the heights of the optical continuum sources and those of the associated hard X-ray sources.For…
On April 23, 2014, the Swift satellite responded to a hard X-ray transient detected by its Burst Alert Telescope, which turned out to be a stellar flare from a nearby, young M dwarf binary DG~CVn. We utilize observations at X-ray, UV,…
Strong magnetic fields are observed in a substantial fraction of upper main sequence stars and white dwarfs. Many such stars are observed to exhibit photometric modulations as the magnetic poles rotate in and out of view, which could be a…
Solar flares radiates energy at all wavelengths, but the spectral distribution of this energy is still poorly known. White-light continuum emission is sometimes observed and the flares are then termed "white-light flares" (WLF). In this…
Variability is a common characteristic of magnetically active stars. Flaring variability is usually interpreted as the observable consequence of transient magnetic reconnection processes happening in the stellar outer atmosphere. Stellar…
The Kepler and TESS space missions significantly expanded our knowledge of what types of stars display flaring activity by recording a vast amount of super-flares from solar-like stars, as well as detecting flares from hotter stars of A-F…
The convective collapse of thin magnetic flux tubes in the photospheres of sun-like stars is investigated using realistic models of the superadiabatic upper convection zone layers of these stars. The strengths of convectively stable flux…
Tsinghua University-Ma Huateng Telescopes for Survey (TMTS) aims to detect fast-evolving transients in the Universe, which has led to the discovery of thousands of short-period variables and eclipsing binaries since 2020. In this paper, we…