A Possible Energy Threshold for Triggered Star Formation
|Date/Time:||Friday, 07 Dec 2012 from 4:10 pm to 5:00 pm|
Massive stars produce copious amounts stellar winds and ionizing radiation before ending their lives as core-collapse supernovae. These forces, collectively known as feedback, sculpt the interstellar medium into bubbles, pillars, and bright rimmed clouds. Stellar feedback may enhance, suppress, or have no net effect on the star formation rate in the surrounding molecular clouds. Theoretical and observational evidence has been published to support all three outcomes. I will present the results of a search for star formation triggered by stellar feedback within the Galactic star forming region, G38.9-0.4. Mid-infrared images from the Spizter GLIMPSE and MIPSGAL surveys show that this region hosts a series of infrared-bright bubbles, likely powered by late-O and early-B stars. Spitzer data, along with near-IR photometry from 2MASS and UKIDSS, reveal over 200 young stellar objects identified through their spectral energy distributions. I will show that this region lacks the signatures of triggered star formation and suggest that late-O stars may not be energetic enough to enhance local star formation. I will also highlight a newly-found sample of compact, embedded star clusters. These clusters may represent one of the youngest phases in cluster formation.