Far-infrared photometry of deeply embedded outflow sources

Abstract

We present far-infrared maps and spectroscopy for a number of deeply embedded protostellar objects (CepE, HH211-MM, IC1396W, L1157, L1211, and RNO15FIR) from data that we acquired with the ISO instruments PHOT and LWS. Several previously undetected deeply embedded sources are found in the vicinity of our targets. We determine temperatures and luminosities of seven objects and locate them on a Lbol-Tbol diagram - the equivalent to a Hertzsprung-Russell diagram for protostars. Their masses and ages, according to their location on tracks taken from our evolutionary model, are derived. L1211 and CepE appear to be intermediate mass objects which will reach final masses of about 3Mo, while the other sources are in or below the solar mass range. The derived ages of 15000 to 30000yr are consistent with their current Class0 state. A comparison of the luminosity of the associated outflows in the 1-0S(1) line of molecular hydrogen with the source properties (bolometric luminosity, bolometric temperature, and envelope mass) of 16 Class0 sources shows no statistically significant correlations. Nevertheless, the data are consistent with a scheme in which the outflow strength and protostar evolve simultaneously. We show that the relationship is partially disguised, however, by the local properties of the surrounding material, the extinction, and short-term flux variability.