Physical Structure of the Proto–Planetary Nebula CRL 618. I. Optical Long‐Slit Spectroscopy and Imaging
Physical Structure of the Proto–Planetary Nebula CRL 618. I. Optical Long‐Slit Spectroscopy and Imaging
In this paper (paper I) we present optical long-slit spectroscopy and imaging of the protoplanetary nebula CRL618. The optical lobes of CRL618 consist of shock-excited gas, which emits many recombination and forbidden lines, and dust, which scatters light from the innermost regions. From the analysis of the scattered Halpha emission, …