Multi-line Herschel/HIFI observations of water reveal infall motions and chemical segregation around high-mass protostars

van Der Tak, Floris
Shipman, Russ
Jacq, T.
Herpin, Fabrice
Braine, J.
Wyrowski, Friedrich

Open link

Publication date

January 2019

DOI

10.1051/0004-6361/201833788

Publisher

EDP Sciences

Abstract

International audience(Abridged) We use HIFI maps of the 987 GHz H2O 2(02)-1(11) emission to measure the sizes and shapes of 19 high-mass protostellar envelopes. To identify infall, we use HIFI spectra of the optically thin C18O 9-8 and H2O-18 1(11)-0(00) lines. The high-J C18O line traces the warm central material and redshifted H2O-18 1(11)-0(00) absorption indicates material falling onto the warm core. We probe small-scale chemical differentiation by comparing H2O 752 and 987 GHz spectra with those of H2O-18. Our measured radii of the central part of the H2O 2(02)-1(11) emission are 30-40% larger than the predictions from spherical envelope models, and axis ratios are <2, which we consider good agreement. For 11 of the 19 sources, we fin...