The abundance of H2O and HDO in Orion KL from Herschel/HIFI
  Using a broadband, high spectral resolution survey toward Orion KL acquired
with Herschel/HIFI as part of the HEXOS key program, we derive the abundances
of H$_2$O and HDO in the different spatial/velocity components associated with
this massive star-forming region: the Hot Core, Compact Ridge, and Plateau. A
total of 20 transitions of H$_2$$^{18}$O, 14 of H$_2$$^{17}$O, 37 of
HD$^{16}$O, 6 of HD$^{18}$O, and 6 of D$_2$O are used in the analysis, spanning
from ground state transitions to over 1200 K in upper-state energy.
Low-excitation lines are detected in multiple components, but the
highest-excitation lines ($E_u >$ 500 K) are well modeled as emitting from a
small ($\sim 2"$) clump with a high abundance of H$_2$O ($\chi = 6.5 \times
10^{-4}$ relative to H$_2$) and a HDO/H$_2$O ratio of 0.003. Using high spatial
resolution ($1.5" \times 1.1"$) images of two transitions of HDO measured by
ALMA as part of its science verification phase, we identify this component as
located near, but not directly coincident with, known continuum sources in the
Hot Core region. Significant HDO/H$_2$O fractionation is also seen in the
Compact Ridge and Plateau components. The outflowing gas, observed with both
emission and absorption components, has a lower HDO/H$_2$O ratio than the
compact components in Orion KL, which we propose could be due to modification
by gas-phase shock chemistry.
