Location

Salt Lake Community College Student Center

Start Date

4-5-2009 1:00 PM

Description

The most massive stars are important contributors to their host galaxies. During their stellar lifetimes, and even in their demise as supernovae, they deposit a great deal of material and energy into their galactic neighborhood, thus providing the building blocks for the next generation of stars. Near the end of their lives, they begin to shed their outer layers into space via a stellar wind, creating what astronomers call a "circumstellar envelope." These envelopes are thus cosmic fossils of the stars themselves. The physics of stellar winds- more generally referred to as "mass loss," is poorly understood. The geometric structure and molecular composition of this circumstellar material can provide important clues to the mass loss process as well as constrain models of stellar evolution. This information can also help inform models of supernova ejecta by providing detailed information about the pre-existing material that the ejecta will slam into as it expands. Previously, these envelopes have been too small to observe from ground or space-based telescopes. The advent of near infrared interferometry has allowed us to resolve these structures for the ¯rst time. A survey of massive stars called Supergiants has been measured using such an instrument; the results of that study are presented here. Support for this work has been generously provided in part by the Rocky Mountain NASA Space Grant Consortium.

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May 4th, 1:00 PM

Stellar Geometries with Spectro-Interferometry

Salt Lake Community College Student Center

The most massive stars are important contributors to their host galaxies. During their stellar lifetimes, and even in their demise as supernovae, they deposit a great deal of material and energy into their galactic neighborhood, thus providing the building blocks for the next generation of stars. Near the end of their lives, they begin to shed their outer layers into space via a stellar wind, creating what astronomers call a "circumstellar envelope." These envelopes are thus cosmic fossils of the stars themselves. The physics of stellar winds- more generally referred to as "mass loss," is poorly understood. The geometric structure and molecular composition of this circumstellar material can provide important clues to the mass loss process as well as constrain models of stellar evolution. This information can also help inform models of supernova ejecta by providing detailed information about the pre-existing material that the ejecta will slam into as it expands. Previously, these envelopes have been too small to observe from ground or space-based telescopes. The advent of near infrared interferometry has allowed us to resolve these structures for the ¯rst time. A survey of massive stars called Supergiants has been measured using such an instrument; the results of that study are presented here. Support for this work has been generously provided in part by the Rocky Mountain NASA Space Grant Consortium.