Axially symmetric superwinds of proto-planetary nebulae with 21 micron dust features

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Astrophysical Journal

DOI:https://doi.org/10.1086/304174· OSTI ID:542139

Meixner, M ^[1]; Skinner, C J ^[1]; Graham, J R ^[2]; Keto, E ^[3]; Jernigan, J G; Arens, J F ^[3]

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1. University of California, Berkeley and Lawrence Livermore National Laboratory
2. Department of Astronomy, 601 Campbell Hall, University of California, Berkeley, California 94720-3411 jrg (at) graham.berkeley.edu
3. Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, P.O. Box 808, L-413, Livermore, California 94551-9900 (United States)

We present narrowband images at selected wavelengths in the 8-13 {mu}m window of four carbon-rich, proto-planetary nebulae that have an unusual 21 {mu}m dust feature: IRAS 04296+3429, IRAS 22272+5435, IRAS 07134+1005, and IRAS 19500{minus}1709. We observe axially symmetric dust emission structures in IRAS 22272+5435 and IRAS 07134+1005, and tentatively in IRAS 19500{minus}1709, while IRAS 04296+3429 is unresolved with our {approximately}1{sup {prime}{prime}} angular resolution. The well-resolved morphology of IRAS 07134+1005 shows an elliptical outer shell surrounding two aligned peaks that we interpret as limb-brightened peaks of an optically thin, elliptical shell with an equatorial density enhancement. This mid-IR morphology contrasts with that observed in the better studied carbon-rich proto-planetary nebulae, AFGL 2688, AFGL 915, and AFGL 618, which show bright, unresolved cores, probably created by optically thick inner regions, and bipolar extensions that align with their optical reflection nebulosities. Using an axially symmetric dust code and assuming that the dust is composed of 0.01 {mu}m amorphous carbon grains, we model the dust emission images and the spectral energy distributions of these four proto-planetary nebulae and of the young, carbon-rich planetary nebula IRAS 21282+5050, which also has an axially symmetric dust shell and other similarities with the proto-planetary nebulae that have the 21 {mu}m dust feature. Marginally resolved mid-infrared images constrain the dust shell{close_quote}s inner radius, while well-resolved mid-infrared images additionally constrain other geometric parameters of the model (e.g., inclination angles and pole-to-equator mass-loss rate ratios). (Abstract Truncated)

• OSTI ID: 542139
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 482; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AXIAL SYMMETRY
COSMIC DUST
GIANT STARS
IMAGES
INFRARED RADIATION
MASS TRANSFER
MATHEMATICAL MODELS
PLANETARY NEBULAE
STELLAR WINDS