Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae

Details Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae

Dec 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998aas...193.1408k&link_type=abstract

American Astronomical Society, 193rd AAS Meeting, #14.08; Bulletin of the American Astronomical Society, Vol. 30, p.1274

Astronomy and Astrophysics

Astronomy

Scientific paper

Velocity-resolved 2.12 micron H_2 maps of the bipolar pre-planetary nebula AFGL 2688 (the Egg Nebula), obtained with the NOAO Phoenix spectrometer, elaborate on previous observations of large velocity gradients in molecular emission both along and perpendicular to the polar axis of the nebula. The measured gradients along the polar axis appear to trace the transition from a ``slow'' ( ~ 20 km s(-1) ), spherically symmetric, asymptotic giant branch (AGB) wind to a faster ( ~ 75 km s(-1) ), collimated, post-AGB wind. Remarkably similar polar velocity gradients are observed in a Phoenix H_2 position-velocity image obtained for the bipolar protoplanetary nebula AFGL 618. These observations support the hypothesis (Weintraub et al. 1998, ApJ, in press) that the shocks delineated by H_2 emission regions in bipolar pre-planetary nebulae form during the post-AGB phases of their central stars. The kinematics of H_2 emission along the equatorial plane of AFGL 2688, meanwhile, are consistent with a model combining spherical expansion with rotation about the polar axis, although a model invoking multiple outflow axes cannot be ruled out. We compare the molecular emission kinematics of AFGL 2688 and AFGL 618 with those of the bipolar planetary nebula NGC 2346, which we also mapped with Phoenix. We also present a polarization map of AFGL 2688 at 4.5 microns, obtained with the Infrared Space Observatory, which we compare with previously published ground-based and Hubble Space Telescope 2 micron polarization maps of the object (Sahai et al. 1998, ApJ, 492, L163).

Affiliated with

Also associated with

No associations

Rating

Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinematics of Molecular Hydrogen Emission from Bipolar Pre-planetary, Protoplanetary, and Planetary Nebulae will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-992932