Circumstellar dust around Red Supergiants in the Local Group: When Smoke Gets in Your Eyes
Abstract
Red supergiants (RSGs) are a short, but critical stage in the lives of 10-40 Mo stars. They suffer significant mass loss (of order 10^-6 Mo/yr). This mass loss is most easily detected from the thermal emission of circumstellar dust. Our recent work has established for the first time that the dust mass loss rates scale nearly linearly with bolometric luminosity for Galactic stars, and we now wish to understand how this relationship scales with metallicity by examining archival data containing RSGs in various Local Group galaxies. Our 4-m and MMT 6.5-m optical spectroscopy, combined with MARCS model atmospheres, have allowed us to determine the physical properties of these stars; we now need to examine the IR data to determine mass-loss rates. We will also use this information to understand what fraction of the dust in these galaxies is due to RSGs. In addition, we will use the archival IRAC and MIPS data to determine what the temperatures are of the dust shells around these stars. When we are done, we will know a lot more about the mass loss process of this short-lived but important evolutionary stage. In addition, we will know about the dust properties, and will have increased our understanding of the dust enrichment of these galaxies.
- Publication:
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Spitzer Proposal
- Pub Date:
- May 2007
- Bibcode:
- 2007sptz.prop40126M