Related papers: HP Lyr - possibly the hottest RV Tau type object

Planets are thought to form at the early stage of stellar evolution when the mass accretion is still ongoing. RY Tau is a T Tauri type star at the age of a few Myr, with accretion disc seen at high inclination, so that line of sight crosses…

Results of the time variability monitoring of the two classical T Tauri stars, RU Lup and IM Lup, are presented. Three photometric data sets were utilised: (1) simultaneous (same field) MOST satellite observations over four weeks in each of…

The binary companion to the peculiar F supergiant HD 172481 is shown to be a Mira variable with a pulsation period of 312 days. Its characteristics are within the normal range found for solitary Miras of that period, although its pulsation…

The nearest accreting T Tauri star, TW Hya was observed with spectroscopic and photometric measurements simultaneous with a long se gmented exposure using the CHANDRA satellite. Contemporaneous optical photometry from WASP-S indicates a…

We present simultaneous EUV and infrared (J,K) observations of the polar HU Aqr obtained during August 1998 when the star was in a high mass accretion state. EUV and IR light curves and EUV spectra are presented and compared with previous…

PSR B1259-63 is a gamma-ray binary system that hosts a pulsar in an eccentric orbit, with a 3.4 year period, around an O9.5Ve star. At orbital phases close to periastron passages, the system radiates bright and variable non-thermal…

The Luminous Blue Variable (LBV) R71 is currently undergoing an eruption, which differs photometrically and spectroscopically from its last outburst in the 1970s. Valuable information on the physics of LBV eruptions can be gained by…

The stellar parameters of RR Lyrae stars vary considerably over a pulsation cycle, and their determination is crucial for stellar modelling. We present a detailed spectroscopic analysis of the pulsating star RR Lyr, the prototype of its…

We report observations of a possible young transiting planet orbiting a previously known weak-lined T-Tauri star in the 7-10 Myr old Orion-OB1a/25-Ori region. The candidate was found as part of the Palomar Transient Factory (PTF) Orion…

HS Hydrae is a short period eclipsing binary (P_orb=1.57 day) that belongs to a rare group of systems observed to have rapidly changing inclinations. This evolution is due to a third star on an intermediate orbit, and results in significant…

The variable star V1129 Cen is classified in the GCVS as being of $\beta$ Lyr type. Unusual for such stars, it exhibits outbursts roughly once a year, lasting for $\sim$40 days. For this reason, a relationship to the dwarf novae has been…

Non-variable OH/IR stars are thought to have just left the asymptotic giant branch (AGB) phase. In this conventional picture, they must still show strong circumstellar extinction caused by the dust ejected during the AGB phase, and the…

HL Tau is one of the most well-studied Class I young stellar objects, including frequent observations at near- and mid-infrared, (sub-) millimeter, and X-ray wavelengths. We present the results of an X-ray variability monitoring campaign…

HD~5501, a hitherto little studied eclipsing binary with an early A-type primary, has been caught in a short-lived, astrophysically interesting phase of its binary evolution. Recent photometric and spectroscopic observations, including…

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.…

The period-change behaviour of 134 RR Lyrae stars in the globular cluster Messier 3 (M3) is investigated on the ~120-year time base of the photometric observations. The mean period-change rates (\beta \approx 0.01 d Myr^-1) of the…

MOST (Microvariability & Oscillations of STars) and ASAS (All Sky Automated Survey) observations have been used to characterize photometric variability of TW Hya on time scales from a fraction of a day to 7.5 weeks and from a few days to 8…

VLTI/AMBER and VLTI/PIONIER observations of the LBV HR Car show an interferometric signature that could not possibly be explained by an extended wind, more or less symmetrically distributed around a single object. Instead, observations both…

RR Lyn is a detached eclipsing binary with a 9.95 d orbit containing two A-stars: one metallic-lined and one possibly metal-poor. We use the light curve from the TESS satellite and two sets of published radial velocity measurements to…

We present the historical light curve of T Tau derived from photographic plates in the Harvard College Observatory archives. We find that the optical light of T Tau varied by 2-3 (or more) magnitudes on time scales as short as a month prior…