2002A&A...383..591H -
Astronomy and Astrophysics, volume 383, 591-597 (2002/2-4)
Gravitationally bound cores in a molecular cirrus cloud.
HEITHAUSEN A., BERTOLDI F. and BENSCH F.
Abstract (from CDS):
Using MAMBO at the IRAM 30m telescope we have observed a dense core in the cirrus cloud MCLD 123.5+24.9 in the dust continuum emission at 250GHz. The core is detected as an elongated filament with an extent of 4.2'x0.7', corresponding to 0.18pcx0.03pc at an adopted distance of 150pc. We find a close correlation between the continuum emission and previously observed C18O (1-0) line emission. Using standard dust models we derive hydrogen column densities of up to 1022cm–2. The total mass for the filament is about 0.66M☉. We also present observations of the HC3N (3-2), (4-3), and (10-9) emission lines obtained with the MPIfR 100m and the IRAM 30m telescopes. The distribution is very different from the dust continuum and the C18O (1-0) line emission. HC3N is concentrated in two distinct clumps located at the ends of the filament seen in the other tracers. Based on a LVG analysis of the HC3N transitions we derive column densities of N(HC3N)/Δv≃1013cm–2/km/s and volume densities of n(H2)≃105cm–3. We find that the HC3N clumps have masses of 0.13 and 0.19M☉. Our data demonstrate that the cirrus cloud cores are gravitationally bound, and that they show chemical structure indicating different evolutionary stages within the cloud.
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Journal keyword(s):
stars: formation - ISM: abundances - ISM: clouds - ISM: individual objects: MCLD 123.5+24.9 - ISM: molecules - ISM: dust
Simbad objects:
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