  CO isotopes are able to probe the different components in protostellar
clouds. These components, core, envelope and outflow have distinct physical
conditions and sometimes more than one component contributes to the observed
line profile. In this study we determine how CO isotope abundances are altered
by the physical conditions in the different components. We use a 3D molecular
line transport code to simulate the emission of four CO isotopomers, 12CO
J=2-1, 13CO J=2-1, C18O J=2-1 and C17O J=2-1 from the Class 0/1 object L483,
which contains a cold quiescent core, an infalling envelope and a clear
outflow. Our models replicate JCMT (James Clerk Maxwell Telescope) line
observations with the inclusion of freeze-out, a density profile and infall.
Our model profiles of 12CO and 13CO have a large linewidth due to a high
velocity jet. These profiles replicate the process of more abundant material
being susceptible to a jet. C18O and C17O do not display such a large linewidth
as they trace denser quiescent material deep in the cloud.
