Related papers: Revisiting the lifetime estimate of large presolar…
The detection of the 11.3-micron emission feature characteristic of the Si--C stretch in carbon-rich evolved stars reveals that silicon carbide (SiC) dust grains are condensed in the outflows of carbon stars. SiC dust could be a significant…
Formation, evolution, and dispersal processes of protoplanetary disks are investigated and the disk lifetime is estimated. Gravitational collapse of a pre-stellar core forms both a central star and a protoplanetary disk. The central star…
Primitive meteorites contain small amounts of presolar minerals that formed in the winds of evolved stars or in the ejecta of stellar explosions. Silicon carbide is the best studied presolar mineral. Based on its isotopic compositions it…
We interpret the interstellar extinction observed towards the Galactic Center (GC) in the wavelength range $\lambda = 1 - 20\,\mkm$. Its main feature is the flat extinction at $3 - 8\,\mkm$ whose explanation is still a problem for the…
Biomolecules can be synthesized in interstellar ice grains subject to UV radiation and cosmic rays. I show that on time scales of $\gtrsim 10^{6}$ years, these processes lead to the formation of large percolation clusters of organic…
We seek to understand the propagation mechanisms of positrons in the interstellar medium (ISM). This understanding is a key to determine whether the spatial distribution of the annihilation emission observed in our Galaxy reflects the…
How dust scatters and absorbs starlight in the interstellar medium (ISM) contains important clues about the size and composition of interstellar dust. While the ultraviolet (UV) and visible interstellar extinction is well studied and can be…
Debris disks are classically considered to be gas-less systems, but recent (sub)millimeter observations have detected tens of those with rich gas content. The origin of the gas component remains unclear; namely, it can be protoplanetary…
We calculate and discuss the chemical evolution of the isotopic silicon abundances in the interstellar medium at distances and times appropriate to the birth of the solar system. This has several objectives, some of which are related to…
Many asteroids show indications they have undergone impacts with meteoroid particles having radii between 0.01 m and 1 m. During such impacts, small dust grains will be ejected at the impact site. The possibility of these dust grains (with…
We put theoretical constraints on the presence and survival of icy grains in debris discs. Particular attention is paid to UV sputtering of water ice, which has so far not been studied in detail in this context. We present a photosputtering…
Bars in gas-rich spiral galaxies are short-lived. They drive gas inflows through their gravity torques, and at the same time self-regulate their strength. Their robustness has been subject of debate, since it was thought that only the…
Dust grains influence many aspects of star formation, including planet formation, opacities for radiative transfer, chemistry, and the magnetic field via Ohmic, Hall, and ambipolar diffusion. The size distribution of the dust grains is the…
We present a mechanism for the crystalline silicate production associated with the formation and subsequent destruction of massive fragments in young protostellar disks. The fragments form in the embedded phase of star formation via disk…
The extinction curve derived from ISO mid-infrared (IR) observations of the Galactic center (GC) exhibits a surprisingly flat behavior in the ~ 3 to 8 micron region, contrary to the deep minimum expected from standard interstellar dust…
We have applied the SRIM computer code to study the sputtering of some likely astrophysical grain materials, and we have shown that selective embedding of metallic projectiles offers a partial explanation of gas-phase depletions. We show…
Shockwaves driven by supernovae both destroy dust and reprocess the surviving grains, greatly affecting the resulting dust properties of the interstellar medium (ISM). While these processes have been extensively studied theoretically,…
Recent observations with dust detectors on board the interplanetary spacecraft Ulysses and Galileo have recorded a substantial flux of large interstellar grains with radii between 0.25 and 2.0 mu entering the solar system from the local…
The timescales on which astronomical dust grows remain poorly understood, with important consequences for our understanding of processes like circumstellar disk evolution and planet formation.A number of post-asymptotic giant branch stars…
The radiative properties of interstellar dust are affected not only by the grain size distribution but also by the grain porosity. We develop a model for the evolution of size-dependent grain porosity and grain size distribution over the…