Related papers: A representative sample of Be Stars I: Sample Sele…
This paper presents the results of spectral observations for the largest complete sample of very luminous IRAS galaxies obtained to date. The sample consists of those 73 objects for which log (L_IR/L_sun) => 11.5 (H0=50 km/s/Mpc, q0=0.5)…
Classical Be (CBe) stars are rapidly rotating B-type stars with Balmer emission lines that originated from the decretion disks surrounding them in their spectra. Accounting for $\sim$20% of all B-type stars, most CBe stars are thought to…
We present the results of a study aimed at assessing the differences in the dis- tribution of rotation speeds, N (v sin i) among young (1-15 Myr) B stars spanning a range of masses 6 < M/M < 12 and located in different environments: 7 low…
Context: Their high intrinsic brightness and small dispersion in absolute magnitude make red clump (RC) stars a prime tracer of Galactic structure and kinematics. Aims: We aim to derive accurate, multi-epoch radial velocities and…
We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra ($\alpha<-0.9$, $S\propto\nu^\alpha$) from the "Big Trio" (RATAN-600-VLA-BTA) project, performed with the "Scorpio" spectrograph on the 6-m telescope of…
Classical Be stars, the "e" standing for the presence of spectroscopic line emission, are main sequence stars of spectral type B that are able to form a gaseous disk in Keplerian motion from star-ejected matter. The main driver of this…
The Carina Nebula is an active star forming region in the southern sky that is of particular interest due to the presence of a large number of massive stars in a wide array of evolutionary stages. Here we present the results of the…
As Be stars are restricted to luminosity classes III-V, but early B-type stars are believed to evolve into supergiants, it is to be expected that the Be phenomenon disappears at some point in the evolution of a moderately massive star,…
We performed the slitless spectroscopic survey to identify Classical (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is…
Aims. We compare the predictions of evolutionary models for early-type stars with atmospheric parameters, projected rotational velocities and nitrogen abundances estimated for a sample of Be-type stars. Our targets are located in 4 fields…
We observed stars with variable radial velocities to determine their spectroscopic orbits. Velocities of 132 targets taken over a time span reaching 30 years are presented. They were measured with the correlation radial velocity…
Previous work statistically identified 5492 optical counterparts, with approximately 90% confidence, from among the approximately 18,000 X-ray sources appearing in the ROSAT All-Sky Survey Bright Source Catalog (RASS/BSC). Using low…
In this work, we update the catalog of OB stars based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) data release 7 and modified the OB stars selection criterion the spectral line indices space. The new catalog…
In the context of the MiMeS survey of magnetism in massive stars, 85 classical Be stars were observed in circular polarization with the aim of detecting magnetic fields at their surfaces. No direct evidence of such fields is found, in…
We present high-dispersion (R~16,000) optical (3900-8700 A) spectra of 390 stars obtained with the Palomar 60 inch telescope. The majority of stars observed are part of the Spitzer Legacy Science Program "The Formation and Evolution of…
We present integrated optical spectrophotometry for a sample of 417 nearby galaxies. Our observations consist of spatially integrated, S/N=10-100 spectroscopy between 3600 and 6900 Angstroms at ~8 Angstroms FWHM resolution. In addition, we…
Classical Be stars are fast rotating, near main sequence B-type stars. The rotation and the presence of circumstellar discs profoundly modify the observables of active Be stars. Our goal is to infer stellar and disc parameters, as well as…
Oxygen abundances of 34 B-type stars in the effective temperature range of Teff~10000-28000K with diversified rotational velocities (vesini~ 0-250km/s) were determined from the OI triplet lines at 7771-5A, with an aim to examine whether…
The majority of massive classical Be stars are thought to be binary interactions products. Their rapid rotation and often strong, variable, and emission-line dominated spectrum, make spectroscopic analysis challenging. Hence, robust binary…
Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution…