M.Sc. project

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Jes Jørgensenhttp://youngstars.nbi.dk/http://www.nbi.dk/~jeskjshapeimage_2_link_0

The formation of protostars is always associated with the ejection of material in the form of collimated jets and outflows. The role of such mass ejection phenomena is crucial for the protostellar evolution; on one hand they provide essential means for the removal of the excess angular momentum which builds up over time as material is transported through the disk onto the protostar. On the other hand, protostellar jets travel at supersonic speeds, and therefore interact violently with the surrounding medium along their passage, in shocks. The impact of such interactions are expectedly more important during the early stages of protostellar evolution, when protostars are still surrounded by a dense envelope of dust and gas. During these stages, jets are believed to efficiently reduce the available mass reservoir which feeds the protostar (e.g., Arce et al. 2006, ApJ, 646, 1070).

This project aims in using the Spitzer mid-infrared spectrograph to map the interaction of jets with their parent protostellar envelopes and further out for a sample of embedded protostars (e.g. L1448, L1157). The analysis of these observations along with data from Herschel, will help to characterize the physical conditions of jet interactions in shocks, but will also to constrain the mass transport and their efficiency in dispersing the protostellar envelope material. In cases of objects with particular interest, existing ancillary data from sub-mm/mm interferometers can be used to assess the detailed morphological structure

The physics of protostellar jets

Keywords: Spitzer mid-IR observations; possible Herschel or submillimeter ancillary data