Observations of the Earliest Stages of Protostellar Disks
First Author:
Jes Jørgensen
Email: jes AT astro.uni-bonn.de
University of Bonn
Auf dem Huegel 71
Bonn, 53121, Germany
Coauthors:
Abstract
Circumstellar disks are likely formed in the early, deeply embedded stages in the evolution of young stellar objects. Their properties are related to the physical and chemical structure of the innermost regions of the centrally condensed envelopes surrounding such protostars. I will present the results from a large survey of about 20 Class 0 and I low-mass protostars using high-angular resolution, submillimeter observations from the Submillimeter Array. These observations are highly complementary to Spitzer observations that detect many of these sources for the first time at mid-infrared wavelengths and provide strong constraints on the physical structure on the inner envelopes and the structure of circumstellar disks. Together these observations paint a picture in which disks form early in the evolution of young low-mass stars: the inferred masses of the central disks are comparable for both Class 0 and I objects, which suggests that disks are formed and grow to significant sizes early in the evolution of the protostars. Line observations of the more evolved Class I systems reveal rotational signatures which in turn constrain the central stellar masses and allows us to trace evolution of the mass of the stars, disks and envelopes through these pivotal stages in protostellar evolution. This study will serve as a pathfinder for large-scale surveys, e.g., of large Spitzer-selected samples, once the Atacama Large Millimeter Array (ALMA) is fully operational.
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