Abstract
Abstract
We present sensitive NH3 (1,1)–(7,7) line images from the Karl G. Jansky Very Large Array toward successive shocks, which are associated with the blueshifted outflow lobe driven by the compact protobinary system L1157. Within a projection distance of 0.1 pc, our observations not only trace the quiescent and cold gas in the flattened envelope, but also illustrate the complex physical and chemical processes that take place where the high-velocity jet impinges on its surrounding medium. Specifically, the NH3 ortho-to-para ratio is enhanced by a factor of 2–2.5 along the jet path, where the velocity offset between the line peak and the blueshifted wing reaches values as high as 10 km s−1; it also shows a strong spatial correlation with the NH3 column density, which is enhanced to >1016 cm−2 toward the shock cavities. At a linear resolution of 1500 au, our refined temperature map from the seven NH3 lines shows a gradient from the warm B0 eastern cavity wall (>120 K) to the cool cavity B1 and the earlier shock B2 (<80 K), indicating shock heating.
Funder
National Natural Science Foundation of China
Ministry of Science and Technology of Taiwan
PRIN-INAF 2016 The Cradle of Life - GENESIS-SKA
European Research Council (ERC) grant agreement
Marie Sklodowska-Curie grant agreement
Publisher
American Astronomical Society
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
4 articles.
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