The following document lists the file abstract/PMYERS_DMARDONE.abs
from catalogue VI/111.
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Near-infrared imaging of IRAS pre-main sequence (PMS) sources often show extended structure of cometary or bipolar appearance surrounding a point source and extending over about 1000 AU. These near-ir extended structures probably result from scattering off the walls of an outflow cavity. The position, size, and orientation of the near-IR extended emission correlates very well with those of the associated bipolar molecular outflows. The most obscured sources (which are also the youngest) have the highest ratio of extended-to-point source flux in the near-infrared, some are completely nebulous at K. These latter objects are the reddest IRAS PMS sources, with spectral energy distributions peaking at 100 um or longer wavelengths. Ground based midinfrared imaging of young relatively high mass protostars often detect extended emission coming from warm dust (100 to 400 K) both in the immediate surroundings of the protostar (circumstellar disk) and in more extended regions presumably due to small grains heated by shock waves within their associated bipolar outflows. However, nobody has done any such imaging projects on low mass protostars due to the high sensitivity required, which is not attainable on ground-based telescopes. We propose to obtain high resolution multiple wavelength ISOCAM images of the youngest known nearby low mass protostars. This will locate accurately the central sources in relation to the outflow cavities and the near-infrared reflection nebulae, and allow detailed models of circumstellar dust heating during the accretion/outflow phases. In particular it will, for the first time, constrain the infall/outflow geometry during the earliest PMS phase for low mass stars. It will also permit a measurement of the heating due to shocks in Herbig-Haro (HH) jets and knots which will constrain current models of HH emission.