Related papers: H$\alpha$ Emission From Active Equal-mass, Wide M …
We have used the HIRES echelle spectrograph in the Keck I telescope to obtain high-resolution spectroscopy of 51 late-type M dwarfs in the Hyades cluster. Cross-correlating the calibrated data against spectra of white dwarfs allows us to…
Hot subdwarfs in close binaries with either M dwarf, brown dwarf or white dwarf companions show unique light variations. In hot subdwarf binaries with M dwarf or brown dwarf companions we can observe the so-called reflection effect and in…
We present a catalog of 857 white dwarf (WD)-M binaries from the sixth data release (DR6) of the Sloan Digital Sky Survey (SDSS), most of which were previously identified. For 636 of them, we complete a spectral analysis and derive the…
We report the results from spectroscopic observations of 113 ultra-wide, low-mass binary systems, composed largely of M0--M3 dwarfs, from the SLoWPoKES catalog of common proper motion pairs identified in the Sloan Digital Sky Survey. Radial…
We report the discovery of two binary M dwarf systems in the immediate solar neighborhood using 2MASS. The first is an M6.5 companion to the nearby G star HD 86728 (Gl 376). The known properties of HD 86728 indicate that the M dwarf (Gl…
We describe a newly-discovered detached M-dwarf eclipsing binary system, the fourth such system known. This system was first observed by the TrES network during a long term photometry campaign of 54 nights. Analysis of the folded light…
The chromospheric emission estimated in the core of different lines, such as Ca II H & K, Na D1 and D2, and Halpha, is not always correlated between lines, as the Ca II H & K and Halpha emission time series are anti-correlated for a few…
We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey using a novel measurement of emission line strength called the Flare Line Index. Each of the ~38,000 M dwarfs in the SDSS low…
Understanding and characterising the magnetic activity of M dwarfs is of paramount importance in the search for Earth-like exoplanets orbiting them. Energetic stellar activity phenomena, such as flares or coronal mass ejections, which are…
2MASSI J1315309-264951 is an L3 dwarf with strong H-alpha emission discovered in the course of a color-selected survey for active galactic nuclei using the Two-Micron All-Sky Survey (2MASS). The strength of its H-alpha emission decreased by…
We present high-resolution echelle spectroscopy of 676 nearby M dwarfs. Our measurements include radial velocities, equivalent widths of important chromospheric emission lines, and rotational velocities for rapidly rotating stars. We…
We present analysis of HST Planetary Camera images of twenty L dwarfs identified in the course of the Two Micron All-Sky Survey. Four of the targets have faint, red companions at separations between 0.07 and 0.29 arcseconds (1.6 to 7.6 AU).…
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid M dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5m and Small \&…
We present the spectroscopic orbits of eleven nearby, mid-to-late M dwarf binary systems in a variety of configurations: two single-lined binaries (SB1s), seven double-lined binaries (SB2s), one double-lined triple (ST2), and one…
Context. M dwarfs are an ideal laboratory for hunting Earth-like planets, and the study of chromospheric activity is an important part of this task. On the one hand, its short-term activity show high levels of magnetic activity that can…
The knowledge of the binary properties of metal-poor and solar-metallicity stars can shed light on the potential differences between the formation processes responsible for both types of objects. The aim of the project is to determine the…
Coherent radio bursts detected from M dwarfs have some analogy with solar radio bursts, but reach orders of magnitude higher luminosities. These events trace particle acceleration, powered by magnetic reconnection, shock fronts (such as…
Stellar activity is ubiquitously encountered in M dwarfs and often characterised by the H$\alpha$ line. In the most active M dwarfs, H$\alpha$ is found in emission, sometimes with a complex line profile. Previous studies have reported…
We analyzed Kepler short-cadence M dwarf observations. Spectra from the ARC 3.5m telescope identify magnetically active (H$\alpha$ in emission) stars. The active stars are of mid-M spectral type, have numerous flares, and well-defined…
Different approaches have been adopted to study short- and long-term stellar magnetic activity, and although the mechanisms by which low-mass stars generate large-scale magnetic fields are not well understood, it is known that stellar…