Related papers: Stellar granulation and interferometry
Sudden changes in the internal structure of stars, placed at the interface between convective and radiative regions, regions of partial ionisation, or between layers that have acquired different chemical composition as a result of nuclear…
In the previous papers in this series, we found that radiative torques can play a major role in the alignment of grains with the interstellar magnetic field. Since the radiative torques can drive the grains to suprathermal rotational…
Stars are not perfectly spherically symmetric. They are deformed by rotation and magnetic fields. Until now, the study of stellar shapes has only been possible with optical interferometry for a few of the fastest-rotating nearby stars. We…
A parametric model of granulation employing a small number of parameters was developed. Synthetic spectra calculated using this model closely match observed spectra and, in particular, reproduce the asymmetries observed in spectral lines.…
We discuss star formation in the turbulent interstellar medium. We argue that morphological appearance and dynamical evolution of the gas is primarily determined by supersonic turbulence, and that stars form via a process we call…
Manifestations of stellar activity (such as star-spots, plage/faculae, and convective flows) are well known to induce spectroscopic signals often referred to as astrophysical noise by exoplanet hunters. For example, setting an ultimate goal…
Asteroseismology provides powerful means to probe stellar interiors. The oscillations frequencies are closely related to stellar interior properties via the density and sound speed profiles. Since these are tightly linked with the mass and…
Spectral-line displacements away from the wavelengths naively expected from the Doppler shift caused by stellar radial motion may originate as convective shifts (correlated velocity and brightness patterns in the photosphere), as…
Rotation is ubiquitous among massive stars. With rotation comes a deformation to the surface geometry, which in turn leads to alterations in the distribution of parameters across the surface including surface gravity, temperature and…
Chemical composition is an important factor that affects stellar evolution. The element abundance on the stellar surface evolves along the lifetime of the star because of transport processes, including atomic diffusion. However, models of…
Since molecules are ubiquitous in space, the study of the 'Molecular Universe' could unfold the mystery of the existing Interstellar medium. Star formation is linked to the chemical evolution processes. Thus, an analysis of the formation of…
Stellar surface processes represent a fundamental limit to the detection of extrasolar planets with the currently most heavily-used techniques. As such, considerable effort has gone into trying to mitigate the impact of these processes on…
The near-surface layers of cool main-sequence stars are structured by convective flows, which are overshooting into the atmosphere. The flows and the associated spatio-temporal variations of density and temperature affect spectral line…
In G dwarfs, the surface distribution, coverage and lifetimes of starspots deviate from solar-like patterns as the rotation rate increases. We set up a numerical platform which includes the large-scale rotational and surface flow effects,…
New constraints on stellar models are provided by large surveys of massive stars, interferometric observations and asteroseismology. After a review of the main results so far obtained, we present new results from rotating models and discuss…
In this paper, I explore various transport processes that have a large impact of the distribution of elements inside stars and thus, on stellar evolution. A heuristic description of the physics behind equations is provided, and key…
Intensity interferometry permits very long optical baselines and the observation of sub-milliarcsecond structures. Using planned kilometric arrays of air Cherenkov telescopes at short wavelengths, intensity interferometry may increase the…
Optical interferometry is a powerful tool to investigate the close environment of AGB stars. With a spatial resolution of a few milli-arcseconds, it is even possible to image directly the surface of angularly large objects. This is of…
During their main sequence evolution, massive stars can develop convective regions very close to their surface. These regions are caused by an opacity peak associated with iron ionization. Cantiello et al. (2009) found a possible connection…
Recent studies of the nearest star-forming clouds of the Galaxy at submillimeter wavelengths with the Herschel Space Observatory have provided us with unprecedented images of the initial conditions and early phases of the star formation…