EDP Sciences
Free access
Volume 437, Number 1, July I 2005
Page(s) 159 - 168
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20041883

A&A 437, 159-168 (2005)
DOI: 10.1051/0004-6361:20041883

A cold globule with a Class 0/I embedded source

ISO observations of the dark cloud DC 303.8-14.2
K. Lehtinen1, K. Mattila1 and D. Lemke2

1  Observatory, Tähtitorninmäki, PO Box 14, 00014 University of Helsinki, Finland
    e-mail: kimmo.lehtinen@helsinki.fi
2  Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany

(Received 23 August 2004 / Accepted 25 February 2005)

Infrared observations of the dark cloud DC 303.8-14.2 and the embedded point source IRAS 13036-7644 have been made with the ISOPHOT instrument aboard ISO at 7.7 $\mu$m, 60 $\mu$m, 100 $\mu$m and 200 $\mu$m. We have compared the properties of dust in DC 303.8-14.2 and the Thumbprint Nebula (TPN), a morphologically similar globule but without star formation. The dust temperature at the center of DC 303.8-14.2 has a minimum of $14.6 \pm 1$ K, similar to that in the TPN. A comparison of far-infrared radial optical depth distributions between these clouds at angular scales of ~1.5´-3´ shows no difference. The observations suggest that there is a bright rim of 7.7 $\mu$m emission that peaks just outside the optical bright rim of the cloud, indicating a halo of very small dust particles or PAHs around the cloud. The bolometric luminosity of the IRAS source is estimated to be about 1.0 $L_{\odot}$. The heating of the cloud by the IRAS source is negligible; the thermal structure of the cloud is dominated by external heating. We have studied the evolutionary status of the IRAS source and find it to be located between Class 0 and Class I, at a late accretion phase. The source was detected at 7.7 $\mu$m and we suggest that this emission is due to the 7.7 $\mu$m UIR band. We also give a compilation of small molecular clouds whose extended FIR emission has been mapped with ISO.

Key words: stars: formation -- ISM: clouds -- ISM: individual objects: DC 303.8-14.2 -- Infrared: ISM -- ISM: individual objects: IRAS 13036-7644

SIMBAD Objects in preparation

© ESO 2005