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arXiv · 0912.4527

Probing the Protostellar Envelope around L1157: the Dust and Gas Connection

Hsin-Fang Chiang·Leslie W. Looney·John J. Tobin·Lee Hartmann
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Abstract

We present observations of the Class 0 protostar L1157-mm using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in 3 mm dust continuum and N2H+ line emission. In the N2H+ line, we detect a large-scale envelope extended over a linear size of ~20,000AU flattened in the direction perpendicular to the outflow. This N2H+ feature coincides with the outer envelope seen in the 8 micron extinction by Looney et al. Meanwhile, the dust continuum traces the compact, nearly spherical structure of the inner envelope, where N2H+ becomes depleted. This highly flattened N2H+ envelope also shows dynamical signatures consistent with gravitational infall in the inner region, but a slow, solid-body rotation at large scales. This flattened structure is not a rotationally supported circumstellar disk; instead, it resembles a prestellar core both morphologically and kinematically, representing the early phase of a Class 0 system. In this paper, we construct a simple model to interpret both the dust continuum and N2H+ emission and suggest a possible dynamical scenario for the overall properties of the envelope.

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Hsin-Fang Chiang, Leslie W. Looney, John J. Tobin, Lee Hartmann. 2009-12-22. Probing the Protostellar Envelope around L1157: the Dust and Gas Connection. https://doi.org/10.1088/0004-637x%2F709%2F1%2F470

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