Identification of Volatiles Toward Young Stellar Objects Kari A. Van Brunt University of MO—St. Louis Advisor: Dr. Erika Gibb

How Did We Get Here?  Key to understanding our solar system  Study other solar systems  Did ours form in a region with low mass YSOs?  Or did ours form in a region with massive stars nearby?  Study composition around YSOs in low mass regions and mixed regions and compare to the composition of our own solar system

Studying Star Forming Regions  Studied at long wavelengths, in the radio and infrared regions  Regions are cold, thus emit radiation at longer wavelengths  Regions are filled with gas and dust, so the wavelength of radiation must be longer than the diameter of the dust particle, or in the submicron region, to be seen  The spectrograph on the space-based telescope, Spitzer covers the >5 µm region

Model of a YSO Outflow Accretion/Inflow Outer Disk Inner Disk

Observations  Used SpeX on IRTF (3m telescope) on Mauna Kea to study ices  Used a spectral range of 2.1-5µm  Resolving power was about 1,700  Data reduced using Spextool  Used NIRSPEC on Keck (10m telescope) to study gases  Used a spectral range of 1-5µm  Resolving power was about 25,000  Data reduced using command line IDL

Ices in GV Tau

 Shape of ice feature is dependent on composition, temperature, and dust grain size  Find the optical depth, fit a mixture of lab ices to the feature, giving the temperature and composition  Find the column density (abundance) by integrating over the optical depth

HCN Gas at ~3µm in GV Tau

Population Diagram  Assume LTE and that the profile is optically thin  Use the Boltzmann Equation to find T:

Discussion  Water ice and carbon monoxide ice have been found in several sources  Analysis is underway  Further observations will be done in June to look for ices in other objects  Observation time has been applied for to obtain better signal- to-noise for the current objects so that the carbon monoxide ice feature can be better resolved  A quick look at the temperature indicates the ice is probably located in the disk rather than in the envelope.  HCN gas has been found in a pilot study of GV Tau  Preliminary results show a temperature of 550 K of the gas  This temperature indicates the gas may be in the disk, accreting onto the star, or in an outflow  Further analysis is ongoing  We will be applying for more time in the fall to characterize gas in other objects

Questions?  Acknowledgments  Missouri-Space Grant Consortium for another year of support!  Dr. Erika Gibb and Dr. Bruce Wilking  Our collaborators, Terrence Rettig and Sean Brittain