Year: 2008
Type: conference-paper
Abstract: Outflows of pre‐main‐sequence stars drive shocks into molecular material within 0.01–1 pc of the young stars. The shock‐heated gas emits infrared lines of H2 and H2O and millimeter and submillimeter lines of many species including CO, SiO, H2S and HCO+. Dust grains are important charge carriers and play a large role in coupling the magnetic field and flow of neutral gas. Some understanding of the effects of the dust on the dynamics of oblique shocks began to emerge in the 1990s. However, detailed models of these shocks are required for the calculation of the grain sputtering contribution to gas phase abundances of species producing observed emissions. We are developing such models.Some of the molecular species introduced into the gas phase by sputtering in shocks or by thermally driven desorption in radiatively heated hot cores form on grain surfaces. Recently laboratory studies have begun to contribute to the understanding of surface reactions and thermally driven desorption important for the chemistry of star forming clouds.Dusty plasmas are prevalent in many evolved stars just as well as in star forming regions. Radiation pressure on dust plays a significant role in mass loss from some post‐main‐sequence stars. The mechanisms leading to the formation of carbonaceous dust in the stellar outflows are similar to those important for soot formation in flames. However, nucleation in oxygen‐rich outflows is less well understood and remains a challenging research area.Dust is observed in supernova ejecta that have not passed through the reverse shocks that develop in the interaction of ejecta with ambient media. Dust is detected in high redshift galaxies that are sufficiently young that the only stars that could have produced the dust were so massive that they became supernovae. Consequently, the issue of the survival of dust in strong supernova shocks is of considerable interest.
Source: AIP conference proceedings
DOI: 10.1063/1.2996715
Institution: University of Leeds
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1561366864