2009/12/22 by Hsin-Fang Chiang, Leslie W. Looney, John J. Tobin +2 · 49 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Circumstellar envelope #Conical surface #Envelope (radar) #Extinction (optical mineralogy) #Geometry #Millimeter #Molecular Spectroscopy and Structure #Optics #Physics #Protostar #Star formation #Stars #Submillimeter Array #Torus #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/709/1/470
published in The Astrophysical Journal 709(1), 470-482 (IOP Publishing) · Accepted for publication by the ApJ, 34 pages, 10 figures and 2 tables
arxiv created 2009/12/22 · openalex publication_date 2010/01/04 · arxiv updated 2014/11/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 N 2 H + line emission. In the N 2 H + line, we detect a large-scale envelope extended over a linear size of ∼20,000 AU flattened in the direction perpendicular to the outflow. This N 2 H + feature coincides with the outer envelope seen in the 8 μm extinction by Looney et al. Meanwhile, the dust continuum traces the compact, nearly spherical structure of the inner envelope, where N 2 H + becomes depleted. This highly flattened N 2 H + 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 N 2 H + emission and suggest a possible dynamical scenario for the overall properties of the envelope.