D. Rouan et al., THE POWER OF ADAPTIVE OPTICS - A CLOSE LOOK AT A MOLECULAR CLOUD IN NGC-2023, Monthly Notices of the Royal Astronomical Society, 284(2), 1997, pp. 395
Observations of the reflection nebula NGC 2023, a region of recent sta
r formation, have revealed small-scale structure in the associated mol
ecular cloud, close to the exciting star, at a spatial resolution of 5
0 to 75 au. These results have been obtained using adaptive optics on
the ESO 3.6-m telescope at La Silla, observing in the H-2 upsilon = 1-
0 S(1) near-IR emission line at 2.121 mu m. Our observations are among
the first to involve the use of adaptive optics combined with spectra
l line resolution. The observed fragment of molecular cloud, a remnant
of the material from which the B-star in NGC 2023 formed, contains a
number of features whose H-2 emission brightness contrast to the surro
unding material is an order of magnitude. These structures are interpr
eted in terms of clumps of gas exhibiting a density contrast of at lea
st an order of magnitude. We discuss the possibility that turbulence p
lays a role in the creation of the observed structures.