Volume 371, Number 1, May III 2001
|Page(s)||287 - 299|
|Published online||15 May 2001|
The kinematics of molecular clumps surrounding hot cores in G29.96-0.02 and G31.41+0.31
Osservatorio Astronomico di Cagliari, Str. 54, Loc. Poggio dei Pini, 09012 Capoterra (CA), Italy
2 Dipartimento di Scienze Fisiche, Università di Cagliari, Cittadella Universitaria, 09042 Monserrato (CA), Italy
3 Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
Corresponding author: L. Testi, email@example.com
Accepted: 15 February 2001
We present high angular resolution interferometric observations of the 3 and 1.3 mm continuum emission, and HCO+(1-0) and SiO(2-1) lines, obtained with the Owens Valley Radio Observatory millimeter-wave array, toward two hot cores (HCs) associated with two well known ultracompact (UC) Hii regions: G29.96-0.02 and G31.41+0.31. These HCs are believed to host young forming massive stars which have been suggested to be surrounded by massive rotating accretion disks. The aim of these new observations is to study the structure and kinematics of the molecular clumps surrounding the HCs and nearby UC Hii regions at moderately high angular resolution. Our observations reveal that the clumps within which the HCs and UC Hii regions are embedded have a complex kinematical structure. The total mass of the clumps is estimated to be in the range 1000-3000 , consistent with previous findings. Our observations also show compelling evidence that the clump in G29.96-0.02 is contracting onto the HC position, suggesting that the accretion process onto the massive young stellar object embedded in the HC is still ongoing. In these objects the kinematical structure that we observe is also compatible with the presence of a massive rotating disk within the HC, even though we cannot prove this suggestion with our data. The case of G31.41+0.31 is more complicated, and our data, although consistent with the presence of an inner disk and an infalling envelope around it, do not have the required spatial resolution to resolve the different structures.
Key words: ISM: clouds / Hii regions / ISM: individual objects: G29.96-0.02, G31.41+0.31 / ISM: molecules / radio lines: ISM
© ESO, 2001
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