K. P. Forde, T. M. Gledhill
We present K-band integral field observations of the circumstellar envelope
of the evolved star OH 231.8+4.2. Spatial and spectral information were
simultaneously acquired using the Sinfoni integral field unit, with adaptive
optics, on the Very Large Telescope. The observations reveal the discovery of
H2 emission (1) around the centre of the nebula and (2) located in clumps along
the Western side of the Northern lobe, presumably associated with the strong
shocks that stimulate the previously reported H-alpha emission at the same
location. An observed H2 1-0/2-1S(1) line ratio of 8.3+/-1.9 was calculated for
the central field, a value consistent with shock excitation.
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http://arxiv.org/abs/1112.1025
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