Related papers: Time-resolved spectroscopy of the planet-hosting s…
We have revisited the sdB+K-star long-period binary PG 1018-047 based on 20 new high-resolution VLT/UVES spectra that provided regular coverage over a period of more than 26 months. We refine the period and establish that the orbit is…
Using the updated oscillation spectrum of $\gamma$ Pegasi, we construct a set of seismic models which reproduce two pulsational frequencies corresponding to the $\ell=0$, p$_1$ and $\ell=1$, g$_1$ modes. Then, we single out models which…
We present a method for finding binaries among pulsating stars that were observed by the Kepler Mission. We use entire four-year light curves to accurately measure the frequencies of the strongest pulsation modes, then track the pulsation…
Subdwarf B (sdB) stars are thought to be core helium burning stars with low mass hydrogen envelopes. In recent years it has become clear that many sdB stars lose their hydrogen through interaction with a binary companion and continue to…
We identify delta Scuti pulsators amongst members of the recently-discovered Cep--Her Complex using light curves from the Transiting Exoplanet Survey Satellite (TESS). We use Gaia colours and magnitudes to isolate a subsample of provisional…
We have obtained time-series spectra for the pulsating hot subdwarf (sdB) PG1605+072. Previous time-series photometry of this star has shown maximum amplitude variations of about 0.1 mag and at least 50 periods. The pulsator has the largest…
The impact of rapid rotation on stellar evolution theory remains poorly understood as of today. Vega is a special object in this context as spectroscopic and interferometric studies have shown that it is a rapid rotator seen nearly pole…
KIC8264293 is a fast rotating B-type pulsator observed by Kepler satellite. Its photometric variability is mainly due to pulsations in high-order g modes. Besides, we detected a weak H$\alpha$ emission. Thus, the second source of…
BK Peg is a double-lined detached eclipsing binary containing two late-F stars in an orbit with small eccentricity. We use light curves from the Transiting Exoplanet Survey Satellite (TESS) and spectroscopic measurements from previous…
We have discovered rotationally split core g-mode triplets and surface p-mode triplets and quintuplets in a terminal age main sequence A star, KIC 11145123, that shows both $\delta$ Sct p-mode pulsations and $\gamma$ Dor g-mode pulsations.…
We present the results of a multi-site photometric campaign carried out in 2004-2008 for the Algol-type eclipsing binary system CT Her, the primary component of which shows Delta Scuti-type oscillations. Our data consist of differential…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
Here, BV(RI)c broad band photometry and intermediate resolution spectroscopy in Halpha region are presented for two rapidly rotating late-type stars: EY Dra and V374 Peg. For a third rapid rotator, GSC 02038-00293, intermediate resolution…
Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich vs.…
We present time-series spectroscopy of the rapidly oscillating Ap star HR 3831. This star has a dominant pulsation period of 11.7 minutes and a rotation period of 2.85 days. We have analysed 1400 intermediate-resolution spectra of the…
UV spectroscopy and spectropolarimetry hold the key to understanding certain aspects of massive stars that are largely inaccessible with optical or longer wavelength observations. This is especially true for the rapidly-rotating Be and Bn…
Context. Thanks to photometric space missions, we have access to more and more information on the properties of white dwarf stars, especially pulsating ones. In the case of pulsators, we have the opportunity to get an insight into their…
By using the most recently published Doppler tomography measurements and accurate theoretical modeling of the oblateness-driven orbital precessions, we tightly constrain some of the physical and orbital parameters of the planetary system…
Among the known groups of pulsating stars, $\delta$ Sct stars are one of the least understood. Theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve…
Three members of the new class of pulsating sdB stars (sdBV or EC 14026 stars) are analysed from Keck HIRES spectra using line blanketed NLTE and LTE model atmospheres. Atmospheric parameters (Teff, log g, He/H), metal abundances and…