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Summary: Astronomy & Astrophysics manuscript no. September 25, 2002
(DOI: will be inserted by hand later)
Farinfrared photometry of deeply embedded outflow sources ?
Dirk Froebrich 1 , Michael D. Smith 2 , Klaus W. Hodapp 3 and Jochen Eisl˜offel 1
1 Th˜uringer Landessternwarte Tautenburg, Sternwarte 5, D07778 Tautenburg, Germany
2 Armagh Observatory, College Hill, Armagh BT61 9DG, Northern Ireland
3 University of Hawaii, Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, USA
Received sooner / Accepted later
Abstract. We present farinfrared maps and spectroscopy for several deeply embedded protostellar objects from data acquired
with the ISO instruments PHOT and LWS. Spectral energy distributions for Cep E, HH 211MM, IC 1396 W, L 1157, L 1211 and
RNO 15 FIR indicate that these are relatively cold Class 0 sources. 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 L bol T bol
diagram -- the equivalent to a HertzsprungRussell diagram for protostars. Their masses and ages, according to their location
on tracks derived from an/our evolutionary model, are derived. L 1211 and Cep E appear to be intermediate mass objects which
will reach final masses of about 3 M , while the other sources are in or below the solar mass range. The derived ages of 15000
to 30000 yr are consistent with their current Class 0 state. A comparison of the luminosity of the associated outflows in the
1 -- 0 S(1) line of molecular hydrogen with the source properties (bolometric luminosity, bolometric temperature and envelope
mass) of 15 Class 0 sources shows no statistically significant correlations. Nevertheless, the data are consistent with a scheme
in which the outflow strength and protostar evolve simultaneously. The relationship is partially disguised, however, by the local
properties of the surrounding material, the extinction and shortterm flux variability.
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