相关论文: White-Light Continuum in Stellar Flares
(abridged) The heating mechanism at high densities during M dwarf flares is poorly understood. Spectra of M dwarf flares in the optical and near-ultraviolet wavelength regimes have revealed three continuum components during the impulsive…
M dwarfs produce explosive flare emission in the near-UV and optical continuum, and the mechanism responsible for this phenomenon is not well-understood. We present a near-UV/optical flare spectrum from the rise phase of a secondary flare,…
The origin of the near-ultraviolet and optical continuum radiation in flares is critical for understanding particle acceleration and impulsive heating in stellar atmospheres. Radiative-hydrodynamic simulations in 1D have shown that high…
We present a homogeneous survey of line and continuum emission from near-ultraviolet (NUV) to optical wavelengths during twenty M dwarf flares with simultaneous, high cadence photometry and spectra. These data were obtained to study the…
The white-light continuum emission of a solar flare remains a puzzle as regards its height of formation and its emission mechanism(s). This continuum, and its extension into the near UV, contain the bulk of the energy radiated by a flare,…
The emission spectrum has been calculated of a homogeneous pure hydrogen layer, which parameters are typical for a flare on a red dwarf. The ionization and excitation states were determined by the solution of steady-state equations taking…
White-light flares are explosive phenomena accompanied by brightening of continuum from near-ultraviolet to optical, which occur on the Sun and stars. In order to investigate the mechanism of white-light flares, we carried out simultaneous…
The near-ultraviolet and optical (white-light) continuum radiation in M dwarf flares exhibits a range of observed characteristics, suggesting that the amount of heating at large optical depth varies among impulsive-type and gradual-type…
We report on radiative hydrodynamic simulations of M dwarf stellar flares and compare the model predictions to observations of several flares. The flares were simulated by calculating the hydrodynamic response of a model M dwarf atmosphere…
We explore the possibility that the continuum emission in stellar flares is powered by nonthermal electrons accelerated during the flares. We compute the continuum spectra from an atmospheric model for a dMe star, AD Leo, at its quiescent…
There are two types of models that explain the appearance of the quasi-blackbody radiation during the impulsive phase of stellar flares. Grinin and Sobolev [Astrophysics, Vol. 13, 348 (1977)] argue that the blue component of the optical…
We present sub-second, continuous-coverage photometry of three flares on the dM3.5e star, EQ Peg A, using custom continuum filters with WHT/ULTRACAM. These data provide a new view of flare continuum emission, with each flare exhibiting a…
The white light during M dwarf flares has long been known to exhibit the broadband shape of a T~10,000 K blackbody, and the white light in solar flares is thought to arise primarily from Hydrogen recombination. Yet, a current lack of broad…
Flares from M-dwarf stars can attain energies up to $10^4$ times larger than solar flares but are generally thought to result from similar processes of magnetic energy release and particle acceleration. Larger heating rates in the low…
White-light stellar flares are now reported by the thousands in long-baseline, high precision, broad-band photometry from missions like Kepler, K2, and TESS. These observations are crucial inputs for assessments of biosignatures in…
It is argued that not only the blue (at the brightness maximum) but also the red (in the slow decay phase) components of the optical continuum of powerful flares on dMe stars are formed near the photosphere. The possible appearance of HeI…
Enhanced continuum brightness is observed in many flares (''white light flares''), yet it is still unclear which processes contribute to the emission. To understand the transport of energy needed to account for this emission, we must first…
M-dwarf flares observed by the \textit{Transiting Exoplanet Survey Satellite} (\textit{TESS}) sometimes exhibit a "peak-bump" light-curve morphology, characterized by a secondary, gradual peak well after the main, impulsive peak. A similar…
The optical and near-ultraviolet (NUV) continuum radiation in M dwarf flares is thought to be the impulsive response of the lower stellar atmosphere to magnetic energy release and electron acceleration at coronal altitudes. This radiation…
On UT 2009 January 16, we observed a white light megaflare on the dM4.5e star YZ CMi as part of a long-term spectroscopic flare-monitoring campaign to constrain the spectral shape of optical flare continuum emission. Simultaneous U-band…