Query : 2002A&A...383..591H

2002A&A...383..591H - Astronomy and Astrophysics, volume 383, 591-597 (2002/2-4)

Gravitationally bound cores in a molecular cirrus cloud.


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.

Abstract Copyright:

Journal keyword(s): stars: formation - ISM: abundances - ISM: clouds - ISM: individual objects: MCLD 123.5+24.9 - ISM: molecules - ISM: dust

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME Polaris Cirrus Cloud MoC 01 52 29.6 +87 40 31           ~ 76 0
2 LDN 1457 DNe 02 55.9 +19 35           ~ 84 1

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