Astron. Astrophys. 333, 702-708 (1998)

Far-infrared ISOPHOT observations and the energy balance of a quiescent globule ^*

K. Lehtinen ¹, D. Lemke ², K. Mattila ¹ and L.K. Haikala <sup>1

1</sup> Observatory, P.O. Box 14, FIN-00014 University of Helsinki, Finland
² Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany

Received 6 October 1997 / Accepted 20 January 1998

Abstract

We have observed a quiescent small globule, the Thumbprint Nebula, with the ISOPHOT far-infrared camera at 100 and 200µm. The observed emission is optically thin thermal emission from dust at a temperature of 14-16 K. The energy budget of the cloud is studied by considering the energy input (interstellar radiation field, ISRF), and outputs (scattered and emitted radiation). It is found that the ISRF is sufficient to be the only heating source of dust in the cloud. We have derived values of absorption cross sections of dust at 100 and 200µm, and found them to be in good agreement with current dust models.

Key words: ISM: clouds dust, extinction ISM: individual objects: Thumbprint Nebula infrared: ISM: continuum

* Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA

Send offprint requests to: K. Lehtinen

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations
• 3. Data processing
• 4. Results
  • 4.1. Surface brightness distribution
  • 4.2. Dust temperature
  • 4.3. Far-infrared opacity
• 5. Discussion
  • 5.1. Heating by the ISRF
  • 5.2. Dust properties
• 6. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: April 20, 1998
helpdesk.link@springer.de