相关论文: Statistical analysis of roAp, He-weak and He-rich …

In this paper we present a new catalogue of Chemically Peculiar (CP) stars obtained by compiling publications in which abundances of metals are provided. Our catalogue includes 428 stars for which the data were obtained through…

This talk is devoted to the statistical analysis of the new catalogue of Chemically Peculiar stars compiled from papers, where chemical abundances of those stars were given. The catalogue contains chemical abundances and physical parameters…

Element abundances of three roAp stars, HD 166473, HD 203932, and HD 217522, were determined using Kurucz model atmospheres with metal abundances scaled to solar ones and the results were compared with data from the literature concerning…

Rapidly oscillating Ap (roAp) stars have rarely been found in binary or higher order multiple systems. This might have implications for their origin. We intend to study the multiplicity of this type of chemically peculiar stars, looking for…

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…

From sector 1--44 {\em TESS} observations, 19 new roAp stars, 103 ostensibly non-peculiar stars with roAp-like frequencies and 617 $\delta$~Scuti stars with independent frequencies typical of roAp stars were found. Examination of all…

The pre-main-sequence evolution of the chemically peculiar (CP) stars on the upper main sequence is still a vast mystery and not well understood. Our analysis of young associations and open clusters aims to find (very) young CP stars to try…

The 60 known rapidly oscillating Ap (roAp) stars are excellent laboratories to test pulsation models in the presence of stellar magnetic fields. Our survey is dedicated to search for new group members in the Northern Hemisphere. We attempt…

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 $\log\,g$,…

(abridged) The three most iron poor stars presently known ([Fe/H] equal to -5.96, -5.4 and -4.75) are carbon-rich, they are called C-Rich Ultra-Metal Poor Stars (CRUMPS). The origin of their peculiar surface abundances is not understood. We…

Aims: Recent observations have challenged our understanding of rotational mixing in massive stars by revealing a population of fast-rotating objects with apparently normal surface nitrogen abundances. However, several questions have arisen…

The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire…

We identify six new CEMP stars ([C/Fe]>+0.7 and [Fe/H]< -1.8) and another seven likely candidates within the APOGEE database following Data Release 12. These stars have chemical compositions typical of metal-poor halo stars, e.g., mean…

We present a homogeneous chemical abundance analysis of 16 elements in 190 metal-poor Galactic halo stars (38 program and 152 literature objects). The sample includes 171 stars with [Fe/H] < -2.5, of which 86 are extremely metal poor,…

High resolution spectra of 5 candidate metal-weak thick-disc stars suggested by Beers & Sommer-Larsen (1995) are analyzed to determine their chemical abundances. The low abundance of all the objects has been confirmed with metallicity…

We report on a programme to monitor the radial velocities of a sample of candidate and confirmed carbon-enhanced, metal-poor (CEMP) stars. We observed 45 targets using the Echelle Spectrographs of three 4m class telescopes. Radial…

We present stellar parameters and metallicities, obtained from a detailed spectroscopic analysis, for a large sample of 98 stars known to be orbited by planetary mass companions (almost all known targets), as well as for a volume-limited…

The chemical compositions of 26 metal-poor stars that exhibit strong CH and/or C2 molecular bands are determined based on high-resolution spectroscopy. We define carbon-enhanced stars taking account of the carbon abundance ratio ([C/Fe])…

We carried out low resolution spectroscopic observations in the wavelength range 3400-4700 A of 20 He-weak and 8 He-strong stars to determine their fundamental parameters by means of the Divan-Chalonge-Barbier (BCD) spectrophotometric…

The magnetic Ap or CP2 stars are natural atomic and magnetic laboratories and ideal testing grounds for the evaluation of model atmospheres. CP2 stars exhibiting photometric variability are traditionally referred to as alpha2 Canum…