Feb 13

"The Symbiotic Relationship between Protostars and their Natal Clouds"
Joel Green, University of Texas at Austin

I explore the relationship between the formation of protostars, and the influence of protostellar outflows on their environment using Spitzer-IRS. Herbig Haro objects are small emission nebulae that signify the interaction between both broad and collimated outflows from young stellar objects and the ambient molecular cloud material. The IRS wavelengths include a wealth of spectral diagnostics to analyze this interaction region, which is resolved in our datacube. First I highlight the first discovery of [O IV], [Ar III], and [Ne V] in a Herbig Haro flow; second I analyze the relationship of [S I] and HD emission to the other species; third I map the region in density and temperature using several independent diagnostics to probe the gas; and finally I present evidence that powerful flows such as HH 168 can unbind a protostar in its early stages of development, opening a ~ 10000 AU cavity of ionized material, and may be capable of unbinding its natal core.

May 1

Molecular Spectroscopy of Planet-Forming Regions in Circumstellar Disks
Colette Salyk, California Institute of Technology

By exploiting the temperature and velocity gradients in circumstellar disks, spectroscopic observations provide a window into the planet-forming regions of disks -- regions that are difficult to spatially resolve. Spectroscopic observations of circumstellar disks obtained with the Keck Near-Infrared Spectrograph (NIRSPEC) and the Spitzer Space Telescope Infrared Spectrograph (IRS) show evidence for a variety of molecules, including CO, H2O, OH, HCN, C2H2 and CO2. Temperatures and lineshapes suggest an origin in the planet-forming (few AU) regions of the disks. I will discuss how these observations are being used to investigate disk structure, chemistry and evolution.