Related papers: Exploring the M-dwarf Luminosity--Temperature--Rad…
Recent studies of the stellar population in the solar neighborhood (<20 pc) suggest that there are undetected white dwarfs (WDs) in multiple systems with main sequence companions. Detecting these hidden stars and obtaining a more complete…
Precision modeling of M dwarfs has become worthwhile in recent years due to the increasingly precise values of masses and radii which can be obtained from eclipsing binary studies. Torres (2013) has identified 4 prime M dwarf pairs with the…
We have measured the angular diameters of six M dwarfs with the CHARA Array, a long-baseline optical interferometer located at Mount Wilson Observatory. Spectral types range from M1.0 V to M3.0 V and linear radii from 0.38 to 0.69 Rsun.…
The NASA K2 mission uses photometry to find planets transiting stars of various types. M dwarfs are of high interest since they host more short period planets than any other type of main sequence stars and transiting planets around M dwarfs…
CONTEXT. The Gaia Collaboration has used Gaia-DR2 sources with six-dimensional (6D) phase space information to derive kinematical maps within 5 kpc of the Sun, which is a reachable range for stars with relative error in distance lower than…
We present metallicities, radial velocities and near-infrared spectral types for 447 M dwarfs determined from moderate resolution (R~2000) near-infrared (NIR) spectra obtained with IRTF/SpeX. These M dwarfs are targets of the MEarth Survey,…
Precise measurements of stellar parameters are required in order to develop our theoretical understanding of stellar structure. These measurements enable errors and uncertainties to be quantified in theoretical models and constrain the…
M-dwarfs are the most abundant stars in the galaxy and popular targets for exoplanet searches. However, their intrinsic faintness and complex spectra inhibit precise characterisation. We only know of dozens of M-dwarfs with fundamental…
Using light curves obtained by the K2 mission, we study the relation between stellar rotation and magnetic activity with special focus on stellar flares. Our sample comprises 56 bright and nearby M dwarfs observed by K2 during campaigns…
We have obtained infrared (1 to 2.5 micron) spectroscopy for 42 halo and disk dwarfs with spectral type M1 to M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard & Hauschildt. Photospheric…
We report progress in the calibration of a method to determine cool dwarf star metallicities using molecular band strength indices. The molecular band index to metallicity relation can be calibrated using chemical abundances calculated from…
The dependence of the cosmic ray intensity on Galactocentric distance is known to be much less rapid than that to be thought-to-be sources: supernova remnants. This is an old problem ('the radial gradient problem') which has led to a number…
We compare radii based on ${\it Gaia}$ parallaxes to asteroseismic scaling relation-based radii of $\sim 300$ dwarfs $\&$ subgiants and $\sim 3600$ first-ascent giants from the ${\it Kepler}$ mission. Systematics due to temperature,…
We obtained high resolution ELODIE and CORALIE spectra for both components of 20 wide visual binaries composed of an F-, G- or K-dwarf primary and an M-dwarf secondary. We analyse the well understood spectra of the primaries to determine…
The Gaia M-dwarf gap is a recently discovered feature in the colour-magnitude diagram that shows a deficiency of low-mass and low-metallicity stars at the lower end of the main sequence. We aim at performing theoretical stellar modelling at…
High-velocity stars are interesting targets to unveil the formation of the Milky Way. In fact they can be recently accreted from an infalling dwarf galaxies or they can be the result of a turbulent merging of galaxies. Gaia is providing the…
M-dwarf stars are the most numerous stars in the Universe; they span a wide range in mass and are in the focus of ongoing and planned exoplanet surveys. To investigate and understand their physical nature, detailed spectral information and…
Context. Radial velocity (RV) measurements from near-infrared spectra have become a potentially powerful tool to search for planets around cool stars and sub-stellar objects. As part of a large survey to characterize M-dwarfs using NIRSPEC…
Time-resolved databases with large spatial coverage are quickly becoming a standard tool for all types of astronomical studies. We report preliminary results from our search for stellar flares in the 2MASS calibration fields. A sample of…
The white dwarf mass-radius relationship is fundamental to modern astrophysics. It is central to routine estimation of DA white dwarf masses derived from spectroscopic temperatures and gravities. It is also the basis for observational…