62 citations · 132 across the 5 of their papers we have counts for
5 papers
The curious conundrum regarding sulfur and oxygen abundances in planetary nebulae
R. B. C. Henry, A. Speck, A. I. Karakas +1
We carefully consider numerous explanations for the sulfur abundance anomaly in planetary nebulae. No one rationale appears to be satisfactory, and we suggest that the ultimate exp…
The interface between the stellar wind and interstellar medium around R Cassiopeiae revealed by far-infrared imaging
T. Ueta, R. E. Stencel, I. Yamamura +11
The circumstellar dust shells of intermediate initial-mass (about 1 to 8 solar masses) evolved stars are generated by copious mass loss during the asymptotic giant branch phase. Th…
Shaping bipolar Planetary Nebulae : How mass loss leads to waistline development
Catharinus Dijkstra, Angela Speck
Asymptotic Giant Branch (AGB) stars generally have spherically symmetric envelopes, whereas most post-AGB stars and Planetary Nebulae (PNe) show axisymmetric circumstellar envelope…
Detection of a Far-Infrared Bow-Shock Nebula Around R Hya: the First MIRIAD Results
T. Ueta, A. K. Speck, R. E. Stencel +10
We present the first results of the MIRIAD (MIPS [Multiband Imaging Photometer for Spitzer] Infra-Red Imaging of AGB [asymptotic giant branch] Dustshells) project using the Spitzer…
The Multitude of Molecular Hydrogen Knots in the Helix Nebula
Margaret Meixner, Peter McCullough, Joel Hartman +2
We present HST/NICMOS imaging of the H_2 2.12 μm emission in 5 fields in the Helix Nebula ranging in radial distance from 250-450" from the central star. The images reveal arcuate…