相关论文: Is the silicate emission feature only influenced b…

We investigate the claim that the ratio {\beta} of radiation pressure force to gravitational force on a dust grain in our solar system can substantially exceed unity for some grain sizes, provided that grain porosity is high enough. For…

We present self-consistent disk models for T Tauri stars which include a parameterized treatment of dust settling and grain growth, building on techniques developed in a series of papers by D'Alessio etal. The models incorporate depleted…

The properties and the evolution of asymptotic giant branch (AGB) stars are strongly influenced by their mass loss through a stellar wind. This is believed to be caused by radiation pressure due to the absorption and scattering of the…

Models of astrophysical dust are key to understand several physical processes, from the role of dust grains as cooling agents in the ISM to their evolution in dense circumstellar disks, explaining the occurrence of planetary systems around…

The spectral energy distributions (SEDs) of some T Tauri stars display a deficit of near-IR flux that could be a consequence of an embedded Jupiter-mass planet partially clearing an inner hole in the circumstellar disc. Here, we use…

The dynamical structure and infrared emission of winds around late-type stars are studied in a self-consistent model that couples the equations of motion and radiative transfer. Both the dynamics and IR spectrum of the solution are fully…

We study here the spontaneous clustering of a submonolayer of grains under horizontal circular shaking. The clustering of grains occurs when increasing the oscillation amplitude beyond a threshold. The dense area travels in a circular…

We present accurate mid-infrared observations of the disk around the young, bona-fide brown dwarf CFHT-BD-Tau 4. We report GEMINI/T-ReCS measurements in the 7.9, 10.4 and 12.3 micron filters, from which we infer the presence of a prominent,…

While it is well recognized that interstellar grains are made of amorphous silicates and some form of carbonaceous materials, it remains debated regarding what exact chemical and physical form the carbonaceous component takes. Contemporary…

We developed a grain growth model that is based on the energy minimisation of surfaces with respect to the volume energy and the grain's environment. We used the well-known FePt L1$_\text{0}$ system to discover the physical factors that…

Grains in disks around young stars grow from interstellar submicron sizes to planetesimals over the course of several Myr. Thermal emission of large grains or pebbles can be best observed at cm wavelengths. However, other emission…

It is generally agreed that interstellar dust grains consist of two main components, namely, silicates and graphites. Some models, like MRN model, assume these grains to be homogeneous spheres following a power law size distribution. This…

We present mid-IR spectroscopy of three T Tauri stars in the young Chamealeon I dark cloud obtained with TIMMI2 on the ESO 3.6m telescope. In these three stars, the silicate emission band at 9.7 micron is prominent. We model it with a…

We present Halpha linear spectropolarimetry of a large sample of Herbig Ae/Be stars. Together with newly obtained data for 17 objects, the sample contains 56 objects, the largest such sample to date. A change in linear polarization across…

Based on the SED, Herbig stars have been categorized into two observational groups, reflecting their overall disk structure: group I members have disks with a higher degree of flaring than their group II counterparts. We investigate the…

The signatures of dust processing and grain growth - related to the formation of rocky planets - are easily seen in mid-infrared spectral features. One important diagnostic tool in this context is the silicate feature in the spectra of…

Silicates are an important component of interstellar dust and the structure of these grains -- amorphous versus crystalline -- is sensitive to the local physical conditions. We have studied the infrared spectra of a sample of ultra-luminous…

The excess emission seen in spectral energy distributions (SEDs) is commonly used to infer the properties of the emitting circumstellar dust in protoplanetary and debris discs. Most notably, dust size distributions and details of the…

Adhesion forces between submicrometer-sized silicate grains play a crucial role in the formation of silicate dust agglomerates, rocky planetesimals, and terrestrial planets. The surface energy of silicate dust particles is the key to their…

We study the effects of using the optical properties of irregular hexahedral grains in photoionization models of circumstellar nebulae around evolved stars. Dust opacities for the irregular grains were obtained from the scattering…