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Astron. Astrophys. 324, 203-210 (1997)


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Four dense molecular cores in the Taurus Molecular Cloud (TMC)

Ammonia and cyanodiacetylene observations

C. Codella 1, R. Welser 1, C. Henkel 1, P.J. Benson 2 and P.C. Myers 3

1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
2 Whitin Observatory Wellesley, Wellesley, Massachusetts 02181, USA
3 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Received 12 July 1996 / Accepted 7 January 1997

Abstract

Trying to obtain a more complete picture of star forming regions in the Taurus molecular cloud, four dense molecular cores (L1521D, L1521F, L1524, L1507A) are identified and mapped through the ammonia (J,K) = (1,1) and (2,2) rotational inversion lines. These cores have sizes from 0.06 to 0.09 pc, hydrogen densities from 0.6 104 to 19.9 104 cm-3 and kinetic temperatures between 7.9 and 9.9 K. The masses range from 0.2 and 1.0 [FORMULA], placing the cores with the lowest M values at the lower edge of the mass distribution for ammonia cores in the TMC. Turbulent, thermal and gravitational energies have been estimated. A comparison between these energy terms and considerations related to thermal and turbulent line broadening indicate that these cores are close to gravitational equilibrium. Moreover, we report detections of the J=9-8 transition of HC5 N towards the ammonia peak positions of these four molecular cores. The HC5 N column densities are between 1.6 1012 and 9.2 1012 cm-2, in agreement with values derived for other molecular cores located in the TMC.

Key words: ISM: clouds – ISM: molecules – radio lines: ISM – ISM: individual objects: TMC

Send offprint requests to: C. Henkel

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998

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