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Deuteration -- the occurrence of deuterium (a "heavy" hydrogen atom,
with a neutron in addition to the proton in the nucleus) in place of a
hydrogen atom in a molecule -- has been used as a tracer of the
evolutionary phases of low- and high-mass star formation. Wienen et
al. have recently studied the amount of deuteration using observations
of the NH2D molecule in a sample of high-mass clumps with the Mopra
and IRAM telescopes.
The high detection rate of NH2D confirms a high deuteration previously
found in massive star-forming clumps. While a higher detection rate
of NH2D is measured in sources at early evolutionary stages, the
deuterium fractionation shows no correlation with evolutionary tracers
such as the rotational temperature between the (1,1) and (2,2)
inversion transition. The figure above (labels removed to highlight
the abstract art nature of the scatter plot) shows NH3 deuteration as
a function of inversion temperature. ATLASGAL clumps that are 70 µm
weak are illustrated as black points, MIR-weak sources as red points,
MIR-bright clumps as green triangles, and compact HII regions as blue
triangles.
The results (with labelled axes!) are published in
Astronomy & Astrophysics.
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