HIFI and SPIRE spectroscopy of HOPS 87: a bright water-rich protostar without an outflow

We propose to use Herschel HIFI and SPIRE to observe emission lines of water and CO in a lowmass Class 0 protostar, HOPS 87 (a.k.a. OMC3 MMS 6N), for which we have characterized the water emission spectrum extensively with SpitzerIRS and HerschelPACS. HOPS 87 is the most luminous source of water emission lines found in a survey of lowmass YSOs, but has very little other emission that could be taken as evidence of a highvelocity outflow; if it truly lacks such an outflow at present it provides a rare opportunity to examine emission from the infalling envelope and potentially the envelopedisk accretion shock. With HIFI spectra we will determine whether or not the water emission arises in a highvelocity outflow, and detect separately the kinematic signatures of the warm inner envelope, the outflowcavity walls, and perhaps the envelopedisk accretion flow. Confirmation of the detection of dense water in the disk accretion flow, which has been suggested as the origin of the midinfrared (2040virgulmicron ) water emission, would be the first unambiguous detection of this flow and is a major goal of this proposal. With SPIRE spectra we will complete our SpitzerIRS and HerschelPACS census of water and CO emission in this object, thereby obtaining a particularly complete and detailed account of physical conditions in the HOPS 87 envelope. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]