110 datasets found

M subdwarfs are low-metallicity M dwarfs that typically inhabit the halo population of the Galaxy. Metallicity controls the opacity of stellar atmospheres; in metal-poor stars,...

Optical (BVRI) photometric measurements of a sample of 564 candidate cool subdwarfs in the nearby halo are presented. The stars generally span the color range...

A search programme for pulsating subdwarf B stars was conducted with the Nordic Optical Telescope on La Palma over 59 nights between 1999 and 2009. The purpose of the programme...

An MK-like spectral classification has been conducted for 1224 hot subdwarf stars with LAMOST DR9 low-resolution spectra. The whole sample was divided into four categories...

The results of a search for cool subdwarfs are presented. Kinematic (U, V, and W) and stellar parameters (Teff, logg, [Fe/H], and Vturb) are derived for 134 candidate subdwarfs...

We present moderate resolution spectroscopy of 111 cool dwarf stars to supplement the observations we have already presented in the Palomar/MSU Nearby-Star Spectroscopic Survey....

The Milky Way galaxy contains a large, spherical component which is believed to harbor a substantial amount of unseen matter. Recent observations indirectly suggest that as much...

White dwarfs are the end state of the evolution of more than 97 per cent of all stars, and therefore carry information on the structure and evolution of the Galaxy through their...

A growing number of eclipsing binary systems of the HW Virginis (HW Vir) kind (i.e. composed by a subdwarf-B/O primary star and an M dwarf secondary) show variations in their...

We report the results of our search for pulsating subdwarf B stars in full frame images, sampled at 30 min cadence and collected during Year 1 of the TESS mission. Year 1 covers...

Evolution of close binaries often proceeds through the common envelope stage. The physics of the envelope ejection (CEE) is not yet understood, and several mechanisms were...

The discovery of extremely zirconium- and lead-rich surfaces amongst a small subgroup of hot subdwarfs has provoked questions pertaining to chemical peculiarity in hot star...

We present an analysis of two pulsating subdwarf B stars PHL 457 and EQ Psc observed during the K2 mission. The K2 light curves of both stars show variation consistent with...

White dwarfs carry information on the structure and evolution of the Galaxy, especially through their luminosity function and initial-to-final mass relation. Very cool white...

The so-called sdA stars are defined by having H-rich spectra and surface gravities similar to hot subdwarf stars, but effective temperature below the zero-age horizontal branch....

Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) represents the adequate framework to handle...

We present an update of our low-resolution spectroscopic follow-up and model atmosphere analysis of hot subdwarf stars from the Galaxy Evolution Explorer (GALEX) survey. Targets...

We present the results of the first spectroscopic follow-up of 132 optically blue ultraviolet (UV)-excess sources selected from the UV-Excess Survey of the Northern Galactic...

About 50 per cent of all known hot subdwarf B stars (sdBs) reside in close (short-period) binaries, for which common-envelope ejection is the most likely formation mechanism....

We have applied the astrometric techniques devised by Murray (1986MNRAS.223..649M) for analysis of 48-inch Schmidt photographic data to SuperCOSMOS scans of UK Schmidt plates...