Elisabetta Tommasi - Stefano Pezzuto
VILSPA - LWS IDT
Two-color diagrams have been widely used as simple diagnostic tool
for identifying young stellar objects in different evolutionary stages.
ISO-LWS spectra offer now the opportunity to improve the capability of
this tool as they give the spectral shape of the sources up to 
allowing, at the same time, to account for the contributions of
the lines in the photometric bands.
We present here a new two-color diagram for young stellar objects and discuss the contributions of far infrared lines to the IRAS fluxes of this sources.
Postscript version