Spectroscopy of the protoplanetary nebula AFGL 618

Westbrook's Molecular Gun: Discovery of Near-ir Micro-structures in Afgl 618

We present high-sensitivity near-IR images of a carbon-rich proto-planetary nebula, AFGL 618, obtained with the Subaru Telescope. These images have revealed “bullets” and “horns” extending farther out from the edges of the previously known bipolar lobes. The spatial coincidence between these near-IR micro-structures and the optical collimated outflow structure, together with the detection of sh...

Multiple Outflows in AFGL 2688

We present high resolution (1. 1×0. 9) imaging of the protoplanetary nebula AFGL 2688 in the CO (J=2–1) line using the IRAM interferometer. The observations reveal with unprecedented detail the structure and the kinematics of the gas ejected by the star over the past few hundred years and exemplify the mechanism by which point symmetries are imprinted on the structure of planetary nebulae at ea...

The synthesis of benzene in the protoplanetary nebula CRL 618 Paul

Physical conditions in the Protoplanetary Nebula CRL 618 derived from observations of vibrationally excited HC 3

We used the Effelsberg 100 m and IRAM 30 m telescopes to observe vibra-tionally excited cyanoacetylene (HC 3 N) in several rotational transitions toward the proto-planetary nebula CRL 618. Lines from 9 different vibrationally excited states with energies ranging up to 1600 K above ground were detected. The lines show P Cygni profiles indicating that the HC 3 N emission originates from an expand...

The chemistry of protoplanetary nebulae

We describe the chemistry occurring in a dense slab of outwardly expanding gas in the post-AGB phase of stellar evolution. Despite the high flux of UV photons from the central star, the intrinsic dust extinction in the slab prevents rapid photodissociation and allows chemical reactions to make a variety of gas-phase species, some complex. We find that chemical evolution ends when the intrinsic ...