相关论文: Decoding the message from meteoritic stardust sili…
Presolar stardust grains found in primitive meteorites are believed to retain the isotopic composition of stellar outflows at the time of grain condensation. Therefore, laboratory measurements of their isotopic ratios represent sensitive…
We present spectroscopic observations of a large sample of Herbig Ae stars in the 10 micrometer spectral region. We perform compositional fits of the spectra based on properties of homogeneous as well as inhomogeneous spherical particles,…
In dense molecular clouds, interstellar grains are covered by mantles of iced molecules. The formation of the grain mantles has two important consequences: it removes species from the gas phase and promotes the synthesis of new molecules on…
We have analyzed the 9.7 and ``18'' micron interstellar silicate absorption features along the line of sight toward four heavily extincted galactic WC-type Wolf-Rayet (WR) stars. We construct two interstellar extinction curves from 1.25 to…
An absorption feature is occasionally reported around 11 microns in astronomical spectra, including those of forming stars. Candidate carriers include water ice, polycyclic aromatic hydrocarbons (PAHs), silicon carbide, crystalline…
Isotope variations of nucleosynthetic origin among Solar System's solid samples are well documented, yet the origin of these variations is still uncertain. The observed variability of \iso{54}Cr among materials formed in different regions…
We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium…
We present dust yields for asymptotic giant branch (AGB) and super--asymptotic giant branch (SAGB) stars of solar metallicity. Stars with initial mass $1.5~M_{\odot} \leq M_{\rm ini} \leq 3~M_{\odot}$ reach the carbon star stage during the…
Rocky asteroids and planets display nucleosynthetic isotope variations that are attributed to the heterogeneous distribution of stardust from different stellar sources in the solar protoplanetary disk. Here we report new high precision…
Scattering and absorption of X-rays by interstellar dust is calculated for a model consisting of carbonaceous grains and amorphous silicate grains. The calculations employ realistic dielectric functions with structure near X-ray absorption…
Dust grains in neutral gas behave as aerodynamic particles, so they can develop large density fluctuations independent of gas density fluctuations. Specifically, gas turbulence can drive order-of-magnitude 'resonant' fluctuations in the…
New silicon carbide (SiC) and aluminum oxide (Al2O3) of a tailor-made microstructure were produced using the ice-templating technique, which permits controlled pore formation conditions within the material. These prototypes will serve to…
We compute the mass and composition of dust produced by stars with masses in the range 1Msun<M<8 Msun and with a metallicity of Z=0.001 during their AGB and Super AGB phases. Stellar evolution is followed from the pre-main sequence phase…
The dusty interstellar medium (ISM) of the Milky Way is distributed in a complex, cloudy structure. It is fundamental to the radiation balance within the Milky Way, provides a reaction surface to form complex molecules, and is the feedstock…
Mineralogical studies of silicate features emitted by dust grains in protoplanetary disks and Solar System bodies can shed light on the progress of planet formation. The significant fraction of crystalline material in comets, chondritic…
Aims. In this paper we study the Spitzer and TIMMI2 infrared spectra of post-AGB disc sources, both in the Galaxy and the LMC. Using the observed infrared spectra we determine the mineralogy and dust parameters of the discs, and look for…
We examine the consequences and implications of the possibility that the best-fit $m$=4/3 line of the silicon isotopic ratios measured in mainstream SiC grains is identical or parallel to to the mean ISM evolution line of the silicon…
Interstellar dust is a major foreground contaminant for many observations and a key component in the chemistry of the interstellar medium, yet its properties remain highly uncertain. Using low-resolution spectra, we accurately measure the…
Context. The largest grains (0.5-1 micron) in the interstellar size distribution are efficient in scattering near- and mid-infrared radiation. These wavelengths are therefore particularly well suited to probe the still uncertain high-end of…
Many studies of especially dust nucleation in winds of carbon-rich AGB stars consider primarily carbon as dust forming material. But dust grains formed in such circumstellar envelopes are rather a mixture of several chemical elements such…