| Name | OT2_mpuravan_2 |
| Title | Shock treatment: breaking the degeneracy on the origin of water emission in protostars |
| URL | http://archives.esac.esa.int/hsa/whsa-tap-server/data?retrieval_type=OBSERVATION&observation_id=1342254245&instrument_name=PACS&product_level=LEVEL0&compress=true |
| DOI | https://doi.org/10.5270/esa-qgsn8tn |
| Author | puravankara, m. |
| Description | What is the origin of the high excitation, mid-IR water lines inprotostars? Two separate shock mechanisms have been proposed: (i) anenvelope-disk accretion shock at the protostellar disk surface and(ii) shocks in outflows. Past studies with Spitzer IRS data have beenunable to conclusively rule out either scenario, despite extensivestudy in recent literature. Doing so for a sample of the earliestprotostars would further our understanding of envelope-disk-protostardynamics and perhaps inform us of the state of a protostellar diskjust after formation.From our high resolution Spitzer IRS survey of 80 protostars in nearbystar forming regions, we have assembled a sample of protostars inwhich strong, high excitation water lines are detected. To resolve thequestion of the origin of water emission, we propose full PACS spatialresolution mapping in the range spectroscopy mode of one of the mostluminous water emitters in our sample.From the PACS maps we will be able to test each shock mechanism in twoways. First, we will investigate the spatial correlation between thepeaks of the water emission, continuum emission, and outflow tracerssuch as the OI, CO (J > 21), and OH lines. Significant spatialoffset between the water emission and the continuum, and the spatialcoincidence of water emission with outflow lines would rule outenvelope-disk accretion shocks. Second, we will model the combined setof PACS and IRS water lines using a large grid of non-LTE models toderive the density and temperature of the water-emitting gas. Highdensity (n>1.0E+10 cm^-3), low temperature (T virgul 200 K) solutions wouldfavor envelope-disk accretion shocks, while low density (n< 1.0E+6cm^-3), high temperature (T > 1000virgulK) solutions would favor theoutflow shocks origin of water. |
| Publication | |
| Instrument | PACS_PacsRangeSpec_point, PACS_PacsRangeSpec_large |
| Temporal Coverage | 2012-10-31T19:40:42Z/2012-11-01T06:25:14Z |
| Version | SPG v14.2.0 |
| Mission Description | 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. |
| Creator Contact | https://support.cosmos.esa.int/h®erschel/ |
| Date Published | 2013-05-01T05:59:04Z |
| Keywords | Herschel, HSC, submillimetre, far-infrared, HIFI, PACS, SPIRE |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, puravankara et al., 2013, 'Shock treatment: breaking the degeneracy on the origin of water emission in protostars', SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-qgsn8tn |