Joint UVA/NRAO Colloquium
| Date & Time | Tuesday November 17, 2009
4:00-5:00pm |
| Location | NRAO Auditorium |
| Title | Observations and Laboratory Studies of Carbon's Evolution Throughout the Galaxy |
| Speaker | Stefanie Milam, NASA Ames & University of Arizona | | Abstract | Observations at millimeter/submillimeter wavelengths of various species can be used to trace the cyclic nature of molecular material, specifically carbon-based, throughout stellar evolution. Studies have shown that the carbon isotopic composition of the interstellar medium suggest a strong dependence upon nearby evolved stars and distance to the Galactic center. However, this can also be affected by the chemical composition, carbon- vs. oxygen-rich, and evolutionary status of these old stars. Observations have recently shown that oxygen-rich circumstellar envelopes have a more complex carbon-chemistry than once considered and may have played a role in interstellar carbon enrichment. As large stars evolve into planetary nebulae, molecular material shed from these objects has been shown to endure this highly destructive phase. Once this expelled matter, comprised of gas and dust, condense into new stars and planetary systems, the material is potentially recycled in a molecular form and on some level preserved. This is traced by the pristine composition of comets, meteors, and interplanetary dust particles. Though the chemistry in these objects can also be much more complex, likely due further chemistry that occurs during their lifecycle. It has also been shown that comets undergo fragmentation events that release organic material into the solar system and may potentially "seed" planets for prebiotic chemistry. I will present some of these observational results and discuss laboratory experiments underway to help trace interstellar/cometary chemistry |
| Additional Information | Coffee will be served at 3:45. |
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