Related papers: Non-Radial Pulsations and Large-Scale Structure in…
Context. Stars experience rapid contraction or expansion at different phases of their evolution. Modelling the angular momentum and chemical elements transport occurring during these phases remains an unsolved problem. Aims. We study a…
It appears that most stars are born in clusters, and that at birth most stars have circumstellar discs which are comparable in size to the separations between the stars. Interactions between neighbouring stars and discs are therefore likely…
Examination of the temporal variability properties of several strong optical recombination lines in a large sample of Galactic Wolf-Rayet (WR) stars reveals possible trends, especially in the more homogeneous WC than the diverse WN…
Observations show that magnetic reconnection and its slow shocks occur in solar flares. The basic magnetic structures are similar for long duration event (LDE) flares and faster compact impulsive (CI) flares, but the former require less…
Veiling is ubiquitous at different wavelength ranges in accreting stars. However, the origin of the veiling in the IR domain is not well understood. The accretion spot alone is not enough to explain the shallow photospheric IR lines in…
Dust grains in the planet forming regions around young stars are expected to be heavily processed due to coagulation, fragmentation and crystallization. This paper focuses on the crystalline silicate dust grains in protoplanetary disks. As…
We describe how the various outcomes of stellar tidal disruption give rise to observable radiation. We separately consider the cases where gas circularizes rapidly into an accretion disc, as well as the case when shocked debris streams…
New multi-epoch, mid-infrared (8-13 microns) spectrophotometric observations are presented for 30~late-type stars. The observations were collected over a four year period (1994-1997), permitting an investigation of the mid-infrared spectral…
The nature of the mechanism responsible for producing the spectacular, geometrically thin, spherical shells found around some carbon stars has been an enigma for some time. Based on extensive radiative transfer modelling of both CO line…
Irregular (Irr) galaxies are gas-rich objects with recent or ongoing star formation. In absence of spiral density waves, star formation occurs largely stochastically. The scattered star-forming regions tend to be long-lived and migrate…
We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We…
Rotation contributes to internal mixing processes and observed variability in massive stars. A significant number of binary stars are not in strict synchronous rotation, including all eccentric systems. This leads to a tidally induced and…
Tidal dissipation is responsible for circularizing the orbits and synchronizing the spins of solar-type close binary stars, but the mechanisms responsible are not fully understood. Previous work has indicated that significant enhancements…
We present modeling research work of the winds and circumstellar environments of prototypical hot and cool massive stars using advanced radiative transfer (RT) calculations. This research aims at unraveling the detailed physics of various…
The atmospheric structure of Mira variables is considerably influenced by pulsation. Molecular absorption lines in the near-infrared (NIR), especially second overtone CO lines, show therefore a characteristic behaviour in time-series of…
We present theoretical continuum emission spectra (SED's), isophotal maps and line profiles for several models of photoevaporating disks at different orientations with respect to the observer. The hydrodynamic evolution of these models has…
Establishing the origin of accretion powered winds from forming stars is critical for understanding angular momentum evolution in the star-disk interaction region. Here, the high velocity component of accretion powered winds is launched and…
Many ultracompact HII regions exhibit a cometary morphology in radio continuum emission. In such regions, a young massive star is probably ablating, through its ultraviolet radiation, the molecular cloud clump that spawned it. On one side…
This paper aims to study the configuration of two components caused by rotational and tidal distortions in the model of a binary system. The potentials of the two distorted components can be approximated to 2nd-degree harmonics.…
Cosmic rays (CRs) are a plausible mechanism for launching winds of cool material from the discs of star-forming galaxies. However, there is no consensus on what types of galaxies likely host CR-driven winds, or what role these winds might…