Related papers: A Plasma Torus Around a Young Low-Mass Star
Stellar oscillations appear all across the Hertzsprung-Russell diagram. Recent theoretical studies support their existence also in the atmospheres of M dwarfs. These studies predict for them short periodicities ranging from 20~min to 3~h.…
We present the serendipitous discovery of 8 distant ($>$ 50 pc) late M dwarfs with plausible associated radio emission at 144 MHz. The M dwarf nature of our sources has been confirmed with optical spectroscopy performed using HET/LRS2 and…
We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion…
We present high resolution Hubble Space Telescope ultraviolet spectroscopy of the dwarf nova EK TrA obtained in deep quiescence. The Space Telescope Imaging Spectrograph data reveal the broad Ly-alpha absorption profile typical of a…
Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years. We compile rotation…
A photometric and spectroscopic analysis of 152 cool white dwarf stars is presented. The discovery of 7 new DA white dwarfs, 2 new DQ white dwarfs, 1 new magnetic white dwarf, and 3 weak magnetic white dwarf candidates, is reported, as well…
We aim to study the optical and near-infrared linear polarimetric properties of a sample of young M7-L7 dwarfs ($\approx$1-500 Myr) with spectroscopic signatures of low- and intermediate-gravity atmospheres. We collected optical ($RIZ$) and…
Over two dozen early F-type variable stars have been identified which constitute a new class of pulsating stars. These stars typically have periods between 0.5 and 3 days with V-band variability of several hundredths of a magnitude. Given…
We present spectroscopy and time-series photometry of the dwarf nova QZ Ser. The spectrum shows a rich absorption line spectrum of type K4 +- 2. K-type secondary stars are generally seen in dwarf novae with orbital periods P-orb around 6 h,…
We present an analysis of K2 light curves (LCs) from Campaigns 4 and 13 for members of the young ($\sim$3 Myr) Taurus association, in addition to an older ($\sim$30 Myr) population of stars that is largely in the foreground of the Taurus…
We report results of Chandra X-ray observations of CI Tau, a young magnetically active classical T Tauri star for which previous studies have reported periodic variability attributed to a massive planet in a short-period orbit. CI Tau was…
We present a study of the variation of spatial structure of stellar populations within dwarf galaxies as a function of the population age. We use deep Hubble Space Telescope/Advanced Camera for Surveys imaging of nearby dwarf galaxies in…
We present a time-variability study of young stellar objects in the cluster IRAS 20050+2720, performed at 3.6 and 4.5 micron with the Spitzer Space Telescope; this study is part of the Young Stellar Object VARiability project (YSOVAR). We…
We report evidence for a planetary companion around the nearby young star HD 70573. The star is a G type dwarf located at a distance of 46 pc with age estimation between 20 and 300 Myrs. We carried out spectroscopic observations of this…
Context. NGC 205 is a peculiar dwarf elliptical galaxy hosting in its center a population of young blue stars. Their origin is still matter of debate, the central fresh star formation activity possibly being related to dynamical…
We present a new sample of $K$-band spectral observations for CVs: non-magnetic and magnetic as well as present day and pre CVs. The purpose of this diverse sample is to address the recent claim that the secondary stars in dwarf novae are…
Variability in Young Stellar Objects (YSOs) is one of their primary characteristics. Long-term, multi-filter, high-cadence monitoring of large YSO samples is the key to understand the partly unusual light-curves that many of these objects…
Many magnetic white dwarfs exhibit a polarised spectrum that periodically varies as the star rotates because the magnetic field is not symmetric about the rotation axis. In this work, we report the discovery that while weakly magnetic white…
Variability is a defining characteristic of young stellar systems, and optical variability has been heavily studied to select and characterize the photospheric properties of young stars. In recent years, multi-epoch observations sampling a…
We present moderate-resolution ($R$$\sim$4000-5000) near-infrared integral field spectroscopy of the young (1-5 Myr) 6-14 $M_\mathrm{Jup}$ companions ROXs 42B b and FW Tau b obtained with Keck/OSIRIS and Gemini-North/NIFS. The spectrum of…