Early stages of star formation are now better understood, following an extensive millimeter-wave study of protostars, which are young stellar objects still deeply embedded in their parent molecular cloud. Thanks to their unprecedented high-resolution maps of the circumstellar environment of many young stellar objects, astronomers Frèdèrique Motte (Max-Planck institute for radioastronomy, Bonn, Germany) and Philippe Andrè (SAp, CEA Saclay, France) find that the radial density in the circumstellar envelopes of protostars depends on the nature of their environment. In isolated protostars, this is well described by a model of spontaneous gravitational collapse proposed by Shu, Adams, and Lizano in 1987, but it is quite different for protostars that form in groups, suggesting a more dynamic collapse driven by external perturbations such as those possibly caused by neighbouring stars in formation. This shows for the first time that the environment of forming stars may partly control the process of star formation itself. These results, obtained by F. Motte and P. Andrè using the IRAM 30-meter radiotelescope, will appear in Astronomy and Astrophysics 365, 440 (January 2001).


Figure 1 : map of the millimeter-wave radiation emitted by the dusty environment of two young stellar objects found in the Taurus star-forming region (Postscript file at : http://wwwusr.obspm.fr/bertout/press/2001-1/Figure1.ps)

Figure 2 : a comparison of the density profiles in protostellar envelopes for several young stellar objects (Postscript file at: http://wwwusr.obspm.fr/bertout/press/2001-1/Figure2.ps)

F. Motte: motte@submm.caltech.edu
P. Andrè: pandre@cea.fr

Astronomy & Astrophysics:
F. Rostas, press contact: francois.rostas@obspm.fr
C. Bertout, Editor-in-Chief: claude.bertout@obspm.fr

Notes for Editors

Figures, complete figure captions, references and background information are available on the Astronomy & Astrophysics Paris Editorial Office website at: http://wwwusr.obspm.fr/bertout/press/2001-1/Release2001-1.html