相关论文: A spectroscopically confirmed Gaia-selected sample…

The 32 Orionis group was discovered almost a decade ago and despite the fact that it represents the first northern, young (age ~ 25 Myr) stellar aggregate within 100 pc of the Sun ($d \simeq 93$ pc), a comprehensive survey for members and…

Our main aim is to test the non-variability of the radial velocity (RV) of a sample of 2351 standard stars used for wavelength calibration of the RVS instrument onboard Gaia. In this paper, we present the spectroscopic analysis of these…

We present a catalog of 531 white dwarf candidates that have large apparent transverse motions relative to the Sun ($v_{T} > 200$ km s$^{-1}$), thus making them likely members of the local Galactic halo population. The candidates were…

Combing Gaia DR2 with LAMOST DR5, we spectroscopically identified 924 hot subdwarf stars, among which 32 stars exhibit strong double-lined composite spectra. We measured the effective temperature $T_{\rm eff}$, surface gravity $\log\,g$,…

We have investigated a group of stars known to have low chromospheric ages, but high kinematical ages. Isochrone, chemical and lithium ages are estimated for them. The majority of stars in this group show lithium abundances much smaller…

The Li abundance observed in pre-main sequence and main sequence late-type stars is strongly age-dependent, but also shows a complex pattern depending on several parameters, such as rotation, chromospheric activity and metallicity. The best…

Based on data from the ESA Gaia Data Release 2 (DR2) and several ground-based, multi-band photometry surveys we compiled an all-sky catalogue of $39\,800$ hot subluminous star candidates selected in Gaia DR2 by means of colour, absolute…

Stellar ages are key to improving our understanding of different astrophysical phenomena. However, many techniques to estimate stellar ages are highly model-dependent. The lithium depletion boundary (LDB), based on the presence or absence…

Young open clusters (t<200 Myr) have been observed to exhibit several peculiarities in their chemical compositions, from a slightly sub-solar iron content, super-solar abundances of some atomic species (e.g. ionised chromium), and atypical…

Context. Only a few open clusters are as important for the study of stellar and substellar objects, and their formation and evolution, as the young sigma Orionis cluster. However, a complete spectroscopic characterisation of its whole…

We have conducted a novel search of most of the southern sky for nearby red dwarfs having low proper motions, with specific emphasis on those with proper motion < 0.18 arcsec yr-1, the lower cutoff of Luyten's classic proper motion catalog.…

The Gaia mission has provided an invaluable wealth of astrometric data for more than a billion stars in our Galaxy. The synergy between Gaia astrometry, photometry, and spectroscopic surveys give us comprehensive information about the Milky…

Nearby late-type stars are excellent targets to look for young objects in stellar associations and moving groups. The study of these groups goes back more than one century ago however, their origin is still misunderstood. Although their…

We present a catalogue of distances, masses and ages for $\sim3$ million stars in the second Gaia data release with spectroscopic parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE and SEGUE. We…

We have conducted a kinematic study of 165 young M dwarfs with ages of <300 Myr. Our sample is composed of stars and brown dwarfs with spectral types ranging from K7 to L0, detected by ROSAT and with photometric distances of <25 pc assuming…

The TW Hya Association (TWA) is a nearby stellar association with an age of $\sim$ 5-10 Myr. This is an important age for studying the late stages of star and planet formation. We measure the parallaxes of 14 candidate members of TWA. That…

We gathered high resolution spectra for an ensemble of 55 bright active and inactive stars using the ARC 3.5 m Telescope Echelle Spectrograph at Apache Point Observatory ($R\approx$31,500). We measured spectroscopic effective temperatures,…

The stellar populations of galaxies hold vital clues to their formation histories. In this paper we present results based on modeling stacked spectra of early-type galaxies drawn from the Sloan Digital Sky Survey (SDSS) as a function of…

Stellar flares are short-duration ($<$ hours) bursts of radiation associated with surface magnetic reconnection events. Stellar magnetic activity generally decreases as a function of both age and Rossby number, $R_0$, a measure of the…

While the majority of massive stars have a stellar companion, most pulsars appear to be isolated. Taken at face value, this suggests that most massive binaries break apart due to strong natal kicks received in supernova explosions. However,…