HIGH-RESOLUTION OBSERVATIONS OF THE CO GAS SURROUNDING THE CORE OF CRL-618

Recently acquired CO(1-0) observations at 115 GHz with the Owens Valle y Radio Observatory have revealed the presence of previously undetecte d material surrounding CRL 618. The observations have a beam size of 2 .0 '' x 1.6 '' and are more sensitive than any interferometric observa tions of the source thus far. Our maps reveal the presence of a circul ar emission region with a radius of approximate to 15 '' surrounding t he core of CRL 618. It is probable that this halo structure is a shell of ejecta from the progenitor of CRL 618, which underwent a period of significant mass loss while ascending the asymptotic giant branch. Th e CO halo is clumpy and surrounds the bright molecular core of CRL 618 , possibly shaping the core's weak. bipolar appearance. As in the case of the CS line we have previously observed, the spectral profile of t he CO line is similar to a P Cygni feature. The morphology of the abso rption feature is that of a point source centered close to, but not co incident with the H II position. In addition, we have imaged the high- velocity outflow from the core, and we find that the redshifted and bl ueshifted emission comes from point sources that are distinctly separa ted, with the redshifted lobe west of the blueshifted lobe.