Related papers: A chemically peculiar Be-shell star in a sub-solar…
New APT photometric observations of HD 97658 by Henry during the current 2012 observing season have failed to confirm the shallow transits of HD 97658b reported below. Additional observations are required to confirm or exclude transits of…
HD~63401 is known magnetic chemically peculiar (mCP) star that shows a slow rotation and probably possesses a hydrodynamically stable stellar atmosphere. In the latter case the atomic diffusion mechanism enforced by the magnetic field can…
HH 50138 is one of the brightest B[e] stars at a distance of $\sim$ 380 pc with strong infrared excess. The star was observed in [O I] 63 $\mu$m and [C II] 158 $\mu$m with high velocity resolution with upGREAT on SOFIA. The velocity…
BD+20 1790 is a young active, metal-rich, late-type K5Ve star. We have undertaken a study of stellar activity and kinematics for this star over the past few years. Previous results show a high level of stellar activity, with the presence of…
We report the discovery of the resolved disk around HD 131835 and present the analysis and modeling of its thermal emission. HD 131835 is a ~15 Myr A2 star in the Scorpius-Centaurus OB association at a distance of 122.7 +16.2 -12.8 parsec.…
The rotating magnetic B stars have oblique dipolar magnetic fields and often anomalous helium and metallic compositions. These stars develop co-rotating torus-shaped clouds by channelling winds from their magnetic poles to an anchored…
Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared (IR) excess and emission lines. The influence of binarity on these phenomena remains controversial. We…
We have found a system listed in the Kepler Binary Catalog (3.273 day period; Prsa et al. 2010) that we have determined is comprised of a low-mass, thermally-bloated, hot white dwarf orbiting an A star of about 2.3 solar masses. In this…
A significant number of Be stars show a second Balmer discontinuity (sBD) attributed to an extended circumstellar envelope (CE). The fast rotational velocity of Be stars undoubtedly plays a significant role in the formation of the CE.…
The viscous decretion disk (VDD) model is able to explain most of the currently observable properties of the circumstellar disks of Be stars. However, more stringent tests, focusing on reproducing multitechnique observations of individual…
We conducted spectroscopic and photometric observations of the optical counterpart of the X-ray transient RX J0117.6-7330 in the Small Magellanic Cloud, during a quiescent state. The primary star is identified as a B0.5 IIIe, with mass M =…
We present new H-band echelle spectra, obtained with the NIRSPEC spectrograph at Keck II, for the massive star cluster "B" in the nearby dwarf irregular galaxy NGC 1569. From spectral synthesis and equivalent width measurements we obtain…
New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 ($V=17.92$ mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute…
We report on a detailed abundance study of six bright, mostly southern, slowly rotating late B stars: HD~1279 (B8III), HD~99803 (B9V), HD~123445 (B9V), HD~147550 (B9V), HD~171961 (B8III) and HD~202671 (B5II/III), hitherto reported as normal…
We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IM Vir, composed of a G7-type primary and a K7 secondary. With these observations we derive…
We intensively studied the flare activity on the stellar object KIC011764567. The star was thought to be solar type, with a temperature of $T_{eff} = (5640 \pm 200)\,$K, $\log(g) = (4.3 \pm 0.3)\,$dex and a rotational period of Prot 22 d…
We present new spectroscopic observations of the early type, double-lined eclipsing binary V446\,Cep. The radial velocities and the photometric data obtained by $Hipparcos$ were analysed for deriving the astrophysical parameters of the…
In the group of B stars with spectroscopic peculiarities, we can find the Be and the B[e] stars. The Be stars are early-type rapid rotators that present, as their principal characteristic, emission lines of hydrogen and singly ionized…
We present photometry and high SNR spectroscopy in the classification region of V635 Cas, the optical counterpart to the transient X-ray pulsator 4U 0115+63, taken at a time when the circumstellar envelope had disappeared. V635 Cas is…
The Be stars display variable optical emission lines originating in the circumstellar disc. Here we analyse high resolution spectroscopic observations of Be stars and the distance between the peaks of H-alpha, H-beta, and H-gamma emission…