Phillips, J. P. and White, G. J.
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12C16O and 13C16O J = 1→0 lines of the dark clouds Heiles 2(TMC-1), L1333, L1778, and L129 are presented. A velocity discontinuity in H I maps of Heiles 2 is reflected in a corresponding CO temperature change, and interpreted as a Mach ~3 shock propagating through a single molecular cloud. It is suggested that TMC-1 has recently emerged from the shock, and that evolutionary factors account for the apparently anomalous occurrence of cyanopolynes in this source. L1333 has two distinct velocity components at -2.3 and +3.6 km s-2 extending over ~0.1 square degrees. Both clouds are rotating, although the orientations of the rotational axes differ significantly. The observations are interpreted in terms of dynamically interacting molecular clouds, a single contracting cloud, and in terms of a cloud through which a high Mach number (M~35) shock is propagating.
In contrast, L1778 and L129 exhibit simple spatial structures showing a central core surrounded by a more diffuse envelope. No evidence for rotation or multiple velocity components is evident. Visual extinction maps made with similar spatial resolution to the molectular data show a general correspondence of the molecules and dust.
|Item Type:||Journal Article|
|Copyright Holders:||1981 Royal Astronomical Society|
|Keywords:||astronomical spectroscopy; carbon monoxide; interstellar gas; molecular clouds; astronomical coordinates; astronomical maps; cyano compounds; optical thickness; shock wave propagation|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||G. J. White|
|Date Deposited:||11 Jun 2012 13:12|
|Last Modified:||24 Feb 2016 09:35|
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