Related papers: HD 203608, a quiet asteroseismic target in the old…
Photometric observations of HD~217522 in 1981 revealed only one pulsation frequency $\nu_1=1.21529$~mHz. Subsequent observations in 1989 showed the presence of an additional frequency $\nu_2=2.0174$~mHz. New observations in 2008 confirm the…
We use the traditional approximation to describe oscillations with frequencies comparable to the angular rotation rate. Validity of this approximation in application to main-sequence B stars is discussed. Numerical results regarding mode…
gamma Dor-type oscillations have been discovered in the star HD218427 through simultaneous uvby photometric observations carried out in the year 2003. A few Hbeta-Crawford measurements were also collected for calibration purposes which…
Studying the internal structure of exoplanets-host stars compared to that of similar stars without detected planets is particularly important for the understanding of planetary formation. The observed overmetallicity of stars around which…
The characterization of the growing number of newly discovered exoplanets ---nature, internal structure, formation and evolution--- strongly relies on the properties of their host-star, i.e. its mass, radius and age. These latter can be…
HD113337 is a Main-Sequence F6V field star more massive than the Sun, hosting one (possibly two) radial velocity (RV) giant planet(s) and a cold debris disk (marked by an infrared excess). We used the VEGA interferometer on the CHARA array…
Uncovering the ingredients and the architecture of planetary systems is a very active field of research that has fuelled many new theories on giant planet formation, migration, composition, and interaction with the circumstellar…
Context: Asteroseismology, a powerful approach for obtaining internal structure and stellar properties, requires surface temperature and chemical composition information to determine mass and age. High-resolution spectroscopy is a valuable…
High resolution spectroscopy and spectropolarimetry have been undertaken at the Anglo-Australian Telescope in order to identify suitable targets for magnetic studies of young sun-like stars, for the proxy study of early solar evolution.…
We have measured transit times for HD 189733b passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband optical photometry of this system was obtained with the MOST…
We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars - HD 79498, HD 155358, HD 197037, and HD 220773 - taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see…
Eclipsing binary stars with an oscillating giant component allow accurate stellar parameters to be derived and asteroseismic methods to be tested and calibrated. To this aim, suitable systems need to be firstly identified and secondly…
A promising way of testing the impact of a magnetic field on internal mixing (core overshooting, internal rotation) in main-sequence B-type stars is to perform asteroseismic studies of a sample of magnetic pulsators. The CoRoT satellite…
We analyze the photometric short-cadence data obtained with the Kepler Mission during the first eight months of observations of two solar-type stars of spectral types G and F: KIC 11395018 and KIC 11234888 respectively, the latter having a…
We present photometric and spectroscopic analyses of gravity (g-mode) long-period pulsating hot subdwarf B (sdB) stars. We perform a detailed asteroseismic and spectroscopic analysis of five pulsating sdB stars observed with {\it TESS}…
The measurement of obliquities in star-planet systems is of great importance for the understanding of planet system formation and evolution. The bright and well studied HAT-P-7 system is intriguing as several Rossiter-McLaughlin (RM)…
We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly averaged velocity measurements for each…
Aims: We want to detect and quantify observables related to accretion processes occurring locally in circumstellar disks, which could be attributed to young forming planets. We focus on objects known to host protoplanet candidates and/or…
Context: KUV 05134+2605 is one of the 21 pulsating DB white dwarfs (V777 Her or DBV variables) known so far. The detailed investigation of the short-period and low-amplitude pulsations of these relatively faint targets requires considerable…
Asteroseismic measurements enable inferences of the underlying stellar structure, such as the density and the speed of sound at various points within the interior of the star. This provides an opportunity to test stellar evolution theory by…