The following document lists the file abstract/JEISLOEF_CLASS0.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
This proposal is an extension of JEISLOEF.H2ROT. While we were originally studying the interaction of outflowing gas from deeply embedded young stellar objects with its environment, we now ask for some additional time to study the outflow sources and their dusty envelopes themselves. Class 0 sources represent the earliest phase in the formation of a young star that we currently know of. These objects have already developed a hydrostatic core, although a major fraction of their final mass is still contained in the surrounding dusty envelope. Since this evolutionary phase is very short-lived (about 10^4 years), and because Class 0 sources are deeply emdedded (so much so that they are not seen even at near-infrared wavelengths), only very few have so far been found. Several of the outflow sources in our original proposal seem to belong to this elusive group and, in the meantime, we have found a number of other, very similar objects, in our ongoing surveys of deeply emdedded outflows from young stellar objects. Obviously, understanding Class 0 sources is vital if we are to understand star formation as a whole; i.e. how does star formation set in, how does the initial protostar form, and how does it develop into a visible pre-main sequence object. With ISOPHOT, we plan to measure the spectral energy distributions of a number of candidate Class 0 sources, so that we may a) put their classification on a firmer basis. b) characterize their surrounding dusty envelopes by deriving their masses, density structures, temperature gradients, and their accretion rates. c) study possible photometric variability compared to the IRAS measurements. d) put constraints on the evolution of the dust in the envelopes. These observations will lead to completely new insights into the earliest phases of star formation, which without ISO would be difficult or indeed impossible for many years to come.