# From clouds to protoplanetary disks: the astrochemical link

4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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Poster session

# CO Spectral Line Energy Distributions in Orion Sources

## Speakers

• Dr. Nick INDRIOLO

## Content

Relative populations in the excited rotational levels of CO are sensitive to conditions in the interstellar medium. Emission lines originating in these levels can thus be used in constraining parameters such as density, temperature, and radiation field. The Herschel Space Observatory has enabled the observation of CO emission lines arising from the $J=4$ through $J=48$ rotational levels, many of which are detected in different sources within the Orion star-forming region. We present observations of CO emission toward Orion KL, Orion H$_2$ Peak 1, Orion South, and the Orion Bar, all of which show distinctive CO spectral line energy distributions (SLEDs) indicating the different excitation mechanisms at work. Using the high spectral resolution HIFI observations, we decompose emission lines into multiple components (e.g., shock, outflow, photodissociation region, ambient cloud) in order to characterize the CO SLED associated with each component. In doing so, we generate templates for the various excitation mechanisms that can be applied toward understanding the processes occurring in unresolved star-forming regions where CO observations have been made.