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| EPoS Contribution |
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An evolutionary sequence of disk-like structures in massive star formation
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Cassandra L. Fallscheer Max-Planck-Institut für Astronomie, Heidelberg, Germany | |
| Three different evolutionary stages of the massive star formation process have been studied looking for supporting evidence for an accretion-based formation scenario of massive stars. The Infrared Dark Cloud IRDC 18223-3 is at one of the earliest observable phases of massive star formation and a velocity gradient traced by CH3OH is indicative of a rotating object oriented orthogonally to the outflow direction. This object is on the order of 28,000 AU in size and does not exhibit Keplerian rotation, but may host a disk within. In the more evolved High Mass Protostellar Object, IRAS 18151-1208, an elongation of approximately 10,000 AU is observed in the 1.3 millimeter dust continuum perpendicular to the outflow. The most evolved source in this study, the hot molecular core IRAS 18507+0121, exhibits the rich chemistry characterizing the hot core phase of massive star formation. Despite the presence of many chemical species, clear signatures of rotation are not detected. However, along the lines of what has been observed in IRAS 18151-1208, a slight elongation in the dust continuum perpendicular to the outflow orientation is detected. Several approaches have been explored as a means of studying whether the observable differences in these massive star formation regions are a result of evolution. Our results are consistent with an accretion based formation mechanism of massive stars, and the structural changes of the observed disk-like objects from large-scale to more compact may be the result of evolution. Modeling efforts which reproduce the observed disk-like structures in the first two case studies will also be discussed. | |
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| Caption: Left: the Ulrich model for infalling gas convolved to the 1.7'' resolution of the data. The modeling results are consistent with the observed velocity gradient (right panel) supporting the interpretation of rotation in this source. Right: the CH3OH velocity moment map of IRDC 18223-3 exhibiting a velocity gradient perpendicular to the outflow. The extent of the flattened rotating object is approximately 27000 AU. | |
| Collaborators: H. Beuther, MPIA, Germany J. Sauter, Univ. of Kiel, Germany Q. Zhang, CfA, USA E. Keto, CfA, USA T.K. Sridharan, CfA, USA |
Key publication
Suggested Session: Massive Stars |