HOPS: Herschel/PACS 70 and 160um obs.

To investigate this, we look at the Orion A and B molecular clouds, home to most of the protostars within 500pc. At ~400pc, Orion is close enough to distinguish individual protostars across a range of environments in terms of both the stellar and gas projected densities.

As part of the Herschel Orion Protostar Survey (HOPS), we used the Photodetector Array Camera and Spectrometer to map 108 partially overlapping square fields with edge lengths of 5' or 8' and measure the 70 and 160{mu}m flux densities of 338 protostars within them. In this paper we examine how these flux densities and their ratio depend on evolutionary state and environment within the Orion complex. We show that Class 0 protostars occupy a region of the 70{mu}m flux density versus 160{mu}m/70{mu}m flux density ratio diagram that is distinct from their more evolved counterparts.