Related papers: Kepler Flares I. Active and Inactive M dwarfs
We observed strong superflares (defined as flares with energy in excess of 10^33 erg) on three late-M dwarfs: 2MASS J08315742+2042213 (hereafter 2M0831+2042; M7 V), 2MASS J08371832+2050349 (hereafter 2M0837+2050; M8 V) and 2MASS…
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…
About 22000 Kepler stars and nearly 60000 TESS stars from sectors 1-24 have been classified according to variability type. A large proportion of stars of all spectral types appear to have periods consistent with the expected rotation…
We present a study of photometric flares on 154 low-mass ($\leq 0.2 \textrm{M}_{\odot}$) objects observed by the SPECULOOS-South Observatory from 1st June 2018 to 23rd March 2020. In this sample we identify 85 flaring objects, ranging in…
We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most are inactive…
On 2017-09-20 we observed GJ 4334, an M5V dwarf rotating with a period of 23.5 days, simultaneously with both the Space Telescope Imaging Spectrograph aboard Hubble (1160 -- 1710 Angstroms) and the Dual Imaging Spectrograph mounted on the…
We present a flare temperature study of the highly active M~dwarf Wolf~359 using simultaneous multiband ($u$, $g$, $r$, $i$, and $z$) photometric observations from the Lulin 1-m and 41-cm telescopes. Twelve flares were detected over five…
We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the W.M. Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most were…
M dwarfs are active stars that exhibit variability in chromospheric emission and photometry at short and long timescales, including long cycles that are related to dynamo processes. This activity also impacts the search for exoplanets…
Photometric space missions like Kepler and TESS continuously discover new exoplanets and advance the search for a second habitable world. The light curves recorded by these telescopes also reveal signs of magnetic activity, such as star…
Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…
Solar radio emission at low frequencies (<1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of…
We study the spectral and temporal behavior of X-ray flares from the active M-dwarf EV Lac in 200 ks of exposure with the Chandra/HETGS. We derive flare parameters by fitting an empirical function which characterizes the amplitude, shape,…
Through the McDonald Observatory M Dwarf Planet Search, we have acquired nearly 3,000 high-resolution spectra of 93 late-type (K5-M5) stars over more than a decade using HET/HRS. This sample provides a unique opportunity to investigate the…
The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type…
We present the results of a coordinated campaign to observe radio and optical stellar flares from the nearby M dwarf flare star EV~Lac. From a total of 27 hours of radio and 29 hours of optical observations, we examine the correspondence of…
We analyzed Kepler light curves of the blazar W2R 1926+42 that provided nearly continuous coverage from quarter 11 through quarter 17 (589 days between 2011 and 2013) and examined some of their flux variability properties. We investigate…
Previous studies of planet occurrence rates largely relied on photometric stellar characterizations. In this paper, we present planet occurrence rates for mid-type M dwarfs using spectroscopy, parallaxes, and photometry to determine stellar…
We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the H$\alpha$ emission line. We…
Stellar 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…