Protostars and Planets VI, Heidelberg, July 15-20, 2013
Warm, dense gas near the massive protostars AFGL 2136 and AFGL 4176 as revealed by water absorption
Indriolo, Nick (Johns Hopkins University)
Neufeld, David (Johns Hopkins University)
Seifahrt, Andreas (University of Chicago)
Richter, Matt (University of California, Davis)
We have detected a multitude of absorption features due to ro-vibrational transitions of water in the near infrared toward the massive protostars AFGL 2136 and AFGL 4176. Transitions arising from over forty different rotational levels with energies between 469 K and 4295 K above ground have been identified, and level populations have been used in concert with a statistical equilibrium code to determine physical parameters such as temperature, density, and total water column density. This analysis for AFGL 2136 results in a temperature of 500 K, water column density of 10^19 cm^-2, and a lower limit to the gas density of 5x10^9 cm^-3. These parameters are suggestive of gas very close to the central protostar. A full analysis of the AFGL 4176 data is currently underway. Our results demonstrate the utility of near infrared observations in determining the physical conditions surrounding massive protostars, and we look to pioneer the use of ground-based observations in studying water in star-forming environments.
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