| date: | 2011 May 18 (Wed) 15:00-16:00 |
| room: |
Kobe University, Science and Technology Research Building #4-809 |
| speaker: | Itsuki Sakon (The University of Tokyo) |
| organizer: | Hiroshi Kimura |
| title: | Observing the Sites of Dust Formation in Circumstellar Environments |
| abstract: |
The process of dust condensation in the gas ejected from stars of various
spectral types during their evolution shall be an important issue to be
demonstrated observationally. While the intermediate- to low-mass stars
are generally expected to play significant roles as the dust budgets in
the Milky Way and in the present universe, massive stars may contribute
efficiently towards the chemical enrichment in the early universe by
providing heavy atoms synthesized during their stellar evolution and
supplying dust grains into the circumstellar space via the stellar
mass-loss activities and the supernova explosions. However, we have quite
a limited knowledge on the compositions and the amount of dust produced
around each type of stars, particularly, from the observational point of
view. We have carried out the multi-epoch mid-infrared observations of periodically dust-forming Wolf-Rayet binaries and dust forming novae taking advantages of the high-spatial resolution capabilities achieved by mid-infrared instruments onboard 8m class ground-based telescopes, aiming to directly demonstrate the sites of dust nucleation in the stellar ejecta. In this presentation, the sites of dust nucleation and the following chemical evolution and/or destruction in the circumstellar environments are discussed based on those mid-infrared imaging and spectroscopic datasets collected so far. |