相关论文: Determining rotational and macroturbulent velociti…

Context: A radial velocity survey of about 380 G and K giant stars is ongoing at Lick observatory. For each star we have a high signal to noise ratio template spectrum, which we use to determine spectroscopic stellar parameters. Aim: The…

Red supergiant stars represent a key phase in the evolution of massive stars. Recent radiative hydrodynamic simulations suggest that their atmospheres may be the location of large-scale convective motions. As supergiant convection is…

Simultaneous, precise measurements of the mass $M$ and radius $R$ of neutron stars can yield uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter. One method that…

We present a comprehensive study that applies the Fourier transform to a sample of O and early B-type stars (either dwarfs, giants, or supergiants) to determine their projected rotational velocities, compare with previous values obtained…

Blue supergiants (BSGs) are key objects for understanding the evolution of massive stars. However, discrepancies between theoretical predictions and empirical observations have opened up important questions yet to be answered. Studying…

We use the proper motions (PM) of half a million red giant stars in Large Magellanic Cloud measured by Gaia to construct a 2d kinematic map of mean PM and its dispersion across the galaxy, out to 7 Kpc from its centre. We then explore a…

We present projected rotational velocity values for 97 Galactic, 55 SMC, and 106 LMC O-B type stars from archival FUSE observations. The evolved and unevolved samples from each environment are compared through the Kolmogorov-Smirnov test to…

Stellar rotation is of key importance for the formation process, evolution, and final fate of massive stars. In this paper we review results from the study of the spin rate properties of a sample of more than 400 Galactic O-type stars…

We present new dynamical parameters of the AR Pav binary system. Ourobservations consist of a series of high resolution optical/NIR spectra from which we derive the radial velocity curve of the red giant as well as its rotation velocity.…

We present a sample of 254,882 luminous red giant branch (LRGB) stars selected from the APOGEE and LAMOST surveys. By combining photometric and astrometric information from the 2MASS and Gaia surveys, the precise distances of the sample…

The mass (M) of a star can be evaluated from its spectroscopically determined effective temperature (T _eff) and metallicity ([Fe/H]) along with the luminosity (L; derived from parallax), while comparing them with grids of theoretical…

The main goal of the Pennsylvania - Torun Planet Search (PTPS) is detection and characterization of planets around evolved stars using the high-accuracy radial velocity (RV) technique. The project is performed with the 9.2 m Hobby-Eberly…

Stellar spectra with a high resolution of 115000 obtained with the HARPS spectrograph provide an opportunity to examine turbulence velocities and their depth distributions in the photosphere of stars. Fourier analysis was performed for 17…

Neutron stars (NSs) in low-mass X-ray binaries rotate at frequencies high enough to significantly deviate from sphericity ($\nu_* \sim$ 200--600 Hz). We investigate the effects of rapid rotation on the observational appearance of a NS. We…

Aim - In this work, a sample of vsini of B9 to F2-type main sequence single stars has been built from highly homogeneous vsini parameters determined for a large sample cleansed from objects presenting the Am and Ap phenomenon as well as…

To determine the actual HI distribution and the velocity field in the outermost disk of the spiral galaxy M33, a tilted-ring model is fitted to 21-cm line data taken with the Arecibo Telescope. Since M33 is one of the main calibrators for…

Turbulent motions in the convective envelope of red giants excite a rich spectrum of solar-like oscillation modes. Observations by CoRoT and Kepler have shown that the mode amplitudes increase dramatically as the stars ascend the red giant…

The structure of a sample of high-redshift (z=2), rotating galaxies with high star formation rates and turbulent gas velocities of sigma=40-80 km/s is investigated. Fitting the observed disk rotational velocities and radii with a Mo, Mao,…

Spectral lines of hot massive stars are known to exhibit large excess broadening in addition to rotational broadening. This excess broadening is often attributed to macroturbulence whose physical origin is a matter of active debate in the…

We have derived relations between full-width-half-maxima and equivalent widths of metallic absorption lines in the spectra of RR~Lyrae stars to estimate new upper limits on the axial equatorial rotational velocities of RR~Lyrae and…