Related papers: The Herbig Ae SB2 System HD 104237
LS 5039 is a gamma-ray binary system observed in a broad energy range, from radio to TeV energies. The binary system exhibits both flux and spectral modulation as a function of its orbital period. The X-ray and very-high-energy (VHE, E >…
Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high…
Analysing a large body of observational data, we found that HD 135160 is a quadruple 2+2 system, composed of a massive ellipsoidal binary ('heartbeat' star) with components Aa and Ab in an eccentric 8.234 d orbit and an eclipsing binary…
We have collected from different surveys some significant spectroscopic data observed from star-forming galaxies in the local Universe. The objects showing a relatively rich spectrum in number of lines from different elements were selected…
The Herbig Ae/Be stars (HAeBes) allow an exploration of the properties of Pre-Main Sequence(PMS) stars above the low-mass range ($<2{\rm\thinspace M_{\odot}}$) and those bordering the high-mass range ($>8{\rm\thinspace M_{\odot}}$). This…
The emission-line Be star HD 215227 lies within the positional error circle of the newly identified gamma-ray source AGL J2241+4454. We present new blue spectra of the star, and we point out the morphological and variability similarities to…
The sulfur abundance is poorly known in most environments. Yet, deriving the sulfur abundance is key to understanding the evolution of the chemistry from molecular clouds to planetary atmospheres. We present observations of H$_2$S 110-101…
Lithium and beryllium are destroyed at different temperatures in stellar interiors. As such, their relative abundances offer excellent probes of the nature and extent of mixing processes within and below the convection zone. We determine Be…
We present the first orbital elements for the massive close binary, HD 101131, one of the brightest objects in the young, open cluster, IC 2944. This system is a double-lined spectroscopic binary in an elliptical orbit with a period of…
We present results of long-slit spectroscopy in several slit positions that cover different morphological structures of the central parts of three bright Galactic HII regions: M8, M17 and NGC7635. We study the spatial distributions of a…
The origin of the strong magnetic fields observed in chemically peculiar Ap and Bp stars stars has long been debated. The recent discovery of magnetic fields in the intermediate mass pre-main sequence Herbig Ae and Be stars links them to Ap…
The intermediate-mass pre-main sequence Herbig Ae/Be stars are key to understanding the differences in formation mechanisms between low- and high-mass stars. The study of the general properties of these objects is hampered by the fact that…
A radial velocity follow-up of the long-period sdOB+G1V type spectroscopic binary SB 744 revealed strong lines of fluorine and lead in the optical spectrum of the sdOB star and subsolar metallicity in the G1V companion. With high-quality…
We have obtained a UVES spectrum of a slowly rotating strongly magnetic Ap star, HD 144897, that exhibits very large overabundances of rare-earth elements. Here we present a detailed spectral analysis of this object, also taking into…
We perform a comprehensive spectroscopic analysis of four such bright sdO stars, namely Feige 34, Feige 67, AGK$+$81 266, and LS II$+$18 9, among which the first three are used as standard stars for flux calibration. We used non-local…
Based on high resolution, high signal-to-noise (S/N) ratio spectra from Keck/HIRES, we have determined abundances of 20 elements for 18 Ba candidates. The parameter space of these stars are in the range of 4880 $\leq$ $\rm{T_{eff}}$ $\leq$…
HD 142527A is one of the most studied Herbig Ae/Be stars with a transitional disk, as it has the largest imaged gap in any protoplanetary disk: the gas is cleared from 30 to 90 AU. The HD142527 system is also unique in that it has a stellar…
The results of spectroscopic study of Ae Herbig star RR Tau are reported. The observations were carried out with a moderate resolution. In accordance with the presented data the Halpha line exhibits a double-peaked emission profile. The…
The eclipsing and double-lined spectroscopic binary system V453 Cygni consists of two early B-type stars, one of which is nearing the terminal age main sequence and one which is roughly halfway through its main sequence lifetime. Accurate…
We present here new observations of the eccentric debris ring surrounding the Gyr-old solar-type star HD 202628: at millimeter wavelengths with ALMA, at far-infrared wavelengths with \textit{Herschel}, and in scattered light with…