Related papers: An observational correlation between stellar brigh…
The theoretically studied impact of rapid rotation on stellar evolution needs to be confronted with the results of high resolution spectroscopy-velocimetry observations. A weak surface magnetic field had recently been detected in the A0…
High-precision photometric observations have revealed ubiquitous stochastic low-frequency photometric variability in early type stars. It has been suggested that this variability arises due to either subsurface convection or internal…
We present a photometric variability survey of young planetary-mass objects using the New Technology Telescope in the Js and Ks bands. Surface gravity plays an important role in the atmospheric structure of brown dwarfs, as young low…
Adding an independent estimate of the mean stellar density, $\rho_{\star}$, as a constraint in the analysis of stars that host transiting exoplanets can significantly improve the precision of the planet radius estimate in cases where the…
We discuss possible tests of the constancy of the velocity of light using distant astrophysical sources such as gamma-ray bursters (GRBs), Active Galactic Nuclei (AGNs) and pulsars. This speculative quest may be motivated by some models of…
Asteroseismology of massive stars has recently begun a revolution thanks to high-precision time series photometry from space telescopes. This has allowed accurate and robust constraints on interior physical processes, such as mixing and…
The study of fundamental properties (such as temperatures, radii, masses, and ages) and interior processes (such as convection and angular momentum transport) of stars has implications on various topics in astrophysics, ranging from the…
Surface granulation of the Sun is primarily a consequence of thermal transport in the outer 1 % of the radius. Its typical scale of about 1 - 2 Mm is set by the balance between convection, free-streaming radiation, and the strong density…
Low amplitude is the defining characteristic of solar-like oscillations. The space projects $Kepler$ and $CoRoT$ give us a great opportunity to successfully detect such oscillations in numerous targets. Achievements of asteroseismology…
To complement hydrodynamic studies of the tidal disruption of the star by a massive black hole, we present the study of stellar luminosity and its variations, produced by the strong gravitational field of the black hole during a close…
A large set of stars observed by CoRoT and Kepler shows clear evidence for the presence of a stellar background, which is interpreted to arise from surface convection, i.e., granulation. These observations show that the characteristic…
Granulation is the observable signature of convection in envelopes of low-mass stars, forming the background in stellar power spectra. While well-studied in evolved giants, granulation on the MS has received less attention. We here study…
An accreting neutron star is potentially the gravitational wave source. In this study, we examine the gravitational wave frequencies from such an object in the steady state, adopting the Cowling approximation. We can derive the empirical…
We present a study of asteroseismically derived surface gravities, masses, and radii of a sample of red giant stars both with and without confirmed planetary companions using TESS photometric light curves. These red giants were drawn from…
Normal-mode oscillation frequencies computed from stellar models differ from those which would be measured from stars with identical interior structures, because of modelling errors in the near-surface layers. These frequency differences…
We present what constraints on opacities can be derived from the analysis of stellar pulsations of BA-type main-sequence stars. This analysis consists of the construction of complex seismic models which reproduce the observed frequencies as…
The radial velocity signature of stellar noise is small, around the meter-per-second, but already too much for the detection of Earth mass planets in habitable zones. In this paper, we address the important role played by observational…
(abridged) We present an analysis of high resolution optical spectra for a sample of very young, mid- to late M, low-mass stellar and substellar objects in Upper Sco and Taurus. Effective temperatures (T_eff) and surface gravities are…
How important is an independent diameter measurement for the determination of stellar parameters of solar-type stars? When coupled with seismic observables, how well can we determine the stellar mass? If we can determine the radius of the…
Localised modelling error in the near-surface layers of evolutionary stellar models causes the frequencies of their normal modes of oscillation to differ from those of actual stars with matching interior structures. These frequency…