2006/09/05 by P. Sonnentrucker, E. González-Alfonso, D. A. Neufeld +5 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Emission spectrum #Infrared #Outflow #Radiative transfer #Shock (circulatory) #Shock wave #Spectral line #Spectrograph #TRACER #astro-ph
paper · pdf · doi:10.1086/508616
published as Astrophys.J.650:L71-L74,2006 · 11 pages, 6 figures, accepted for publication in ApJL
arxiv created 2006/09/05 · openalex publication_date 2006/10/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report the first detection of gas-phase CO 2 emission in the star-forming region Cepheus A East, obtained by spectral line mapping of the ν 2 bending mode at 14.98 μm with the Infrared Spectrograph on board the Spitzer Space Telescope . The gaseous CO 2 emission covers a region about 35'' × 25'' in extent and results from radiative pumping by 15 μm continuum photons emanating predominantly from the HW2 protostellar region. The gaseous CO 2 exhibits a temperature distribution ranging from 50 to 200 K. A correlation between the gas-phase CO 2 distribution and that of H 2 S (2), a tracer of shock activity, indicates that the CO 2 molecules originate in a cool postshock gas component associated with the outflow powered by HW2. The presence of CO 2 ice absorption features at 15.20 μm toward this region and the lack of correlation between the IR continuum emission and the CO 2 gas emission distribution further suggest that the gaseous CO 2 molecules are mainly sputtered off grain mantles (by the passage of slow nondissociative shocks with velocities of 15-30 km s -1 ) rather than sublimated through grain heating.