|Intermediate Mass YSOs: getting to the core of the matter
|Due to a dramatic increase in gas-phase abundance above temperatures of 100 K, water emission illuminates the important .milestones. of star formation. Gravitational collapse, accretion shocks, protostellar heating of envelopes and disks, and the injection and motion of outflows into the protostellar envelope all glow in water. At the same time, water in absorption probes the conditions of the cold gas. Determination of water abundance throughout the envelope allows us to place strong constraints on the the physical structure of the envelope and energy transfer occurring within it. Analysis of H2O and H2018O transitions observed with HIFI towards intermediate mass Young Stellar Objects have shown that, contrary to expectations, the ground state H2-18O line (547.676 GHz) does not trace the warm inner envelope. Test observations towards two of our sources have confirmed model predictions that the higher excitation line at 1095.627 GHz can be used to probe the warm inner envelope and hot core. Following this result, we propose to observe the remaining intermediate mass YSOs on our source list. We request 12.3 hours to perform HIFI DBS observations in band 4b in order that we may determine the water abundance in the inner regions of these proto-stellar envelopes.
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2013, OT2_cmccoey_2, SPG v14.1.0. https://doi.org/10.5270/esa-hr5kwtk