PT Journal
AU Melnick, GJ
   Tolls, V
   Neufeld, DA
   Bergin, EA
   Phillips, TG
   Wang, S
   Crockett, NR
   Bell, TA
   Blake, GA
   Cabrit, S
   Caux, E
   Ceccarelli, C
   Cernicharo, J
   Comito, C
   Daniel, F
   Dubernet, M
   Emprechtinger, M
   Encrenaz, P
   Falgarone, E
   Gerin, M
   Giesen, TF
   Goicoechea, JR
   Goldsmith, PF
   Herbst, E
   Joblin, C
   Johnstone, D
   Langer, WD
   Latter, WD
   Lis, DC
   Lord, SD
   Maret, S
   Martin, PG
   Menten, KM
   Morris, P
   Müller, HSP
   Murphy, JA
   Ossenkopf, V
   Pagani, L
   Pearson, JC
   Pérault, M
   Plume, R
   Qin, S
   Salez, M
   Schilke, P
   Schlemmer, S
   Stutzki, J
   Trappe, N
   van der Tak, FFS
   Vastel, C
   Yorke, HW
   Yu, S
   Zmuidzinas, J
TI Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H[sub:2]O and its isotopologues towards Orion KL
SO Astron. Astrophys.
PY 2010
BP L27
VL 521
DI 10.1051/0004-6361/201015085
DE HEB mixer applications; HIFI; Herschel; ISM: abundances / ISM: molecules
AB We report the detection of more than 48 velocity-resolved ground rotational state transitions of H216O, H218O, and H217O – most for the first time – in both emission and absorption toward Orion KL using Herschel/HIFI. We show that a simple fit, constrained to match the known emission and absorption components along the line of sight, is in excellent agreement with the spectral profiles of all the water lines. Using the measured H218O line fluxes, which are less affected by line opacity than their H216O counterparts, and an escape probability method, the column densities of H218O associated with each emission component are derived. We infer total water abundances of 7.4 × 10-5, 1.0 × 10-5, and 1.6 × 10-5 for the plateau, hot core, and extended warm gas, respectively. In the case of the plateau, this value is consistent with previous measures of the Orion-KL water abundance as well as those of other molecular outflows. In the case of the hot core and extended warm gas, these values are somewhat higher than water abundances derived for other quiescent clouds, suggesting that these regions are likely experiencing enhanced water-ice sublimation from (and reduced freeze-out onto) grain surfaces due to the warmer dust in these sources.
ER