The Illumination and Growth of CRL 2688: An Analysis of New & Archival HST Observations

Abstract

We present four-color images of CRL 2688 obtained in 2009 using the Wide-Field Camera 3 on HST. The F606W image is compared with archival images in very similar filters to monitor the proper motions of nebular structure. We find that the bright N-S lobes have expanded uniformly by 2.5% and that the ensemble of rings has translated radially by 0.07 in 6.65 y. The rings were ejected every 100y for ~4 millennia until the lobes formed 250y ago. Starlight scattered from the edges of the dark E-W dust lane is coincident with extant H2 images and leading tips of eight pairs of CO outflows. We interpret this as evidence that fingers lie within geometrically opposite cones of opening angles {\approx} 30{\circ} like those in CRL618. By combining our results of the rings with 12CO absorption from the extended AGB wind we ascertain that the rings were ejected at ~18 km s-1 with very little variation and that the distance to CRL2688, v_{exp}$/${\dotθ}_exp$, is 300 - 350 pc. Our 2009 imaging program included filters that span 0.6 to 1.6μm. We constructed a two-dimensional dust scattering model of stellar radiation through CRL2688 that successfully reproduces the details of the nebular geometry, its integrated spectral energy distribution, and nearly all of its color variations. The model implies that the optical opacity of the lobes >~ 1, the dust particle density in the rings decreases as radius^{-3} and that the mass and momentum of the AGB winds and their rings have increased over time.

(51 pages, 6 figures; accepted by ApJ)

References in corpus (4)

• Stellar Models and Yields of Asymptotic Giant Branch Stars
• 2D Models for Dust-driven AGB Star Winds
• Minkowski's Footprint revisited. Planetary Nebula formation from a single sudden event?
• Envelope density pattern around wide binary AGB stars: a dynamical model

Cited by in corpus (16)

• Planetary Nebulae: Sources of Enlightenment
• Outflows from Evolved Stars: The Rapidly Changing Fingers of CRL618
• Rings and arcs around evolved stars. II. The Carbon Star AFGL 3068 and the Planetary Nebulae NGC 6543, NGC 7009 and NGC 7027
• Panchromatic HST/WFC3 Imaging Studies of Young, Rapidly Evolving Planetary Nebulae. II. NGC 7027
• Multiple Fast Molecular Outflows in the PPN CRL 618
• A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL 2688 in the 3mm and 1.3mm Windows
• Molecules in the carbon-rich protoplanetary nebula CRL 2688
• The Chemical composition of the post-AGB F-supergiant CRL 2688
• Multi-epoch Optical Images of IRC+10216 Tell About the Central Star And the Adjacent Environment
• Evolution from Spherical AGB Wind to Multipolar Outflow in Pre-Planetary Nebula IRAS 17150-3224
• Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes
• Rings and arcs around evolved stars -- III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
• Emerging planetary nebulae within 3D spiral patterns
• Differential Proper-Motion Measurements of The Cygnus Egg Nebula: The Presence of Equatorial Outflow
• 3-D structures of planetary nebulae
• A Dust-Scattering Model for M1-92: A Revised Estimate of the Mass Distribution and Inclination