2000/02/14 by Joseph L. Hora, Hora, Joseph L., William B. Latter +13
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0002289
4 pages, 3 figures, To appear in ``Asymmetrical Planetary Nebulae II: from Origins to Microstructures,'' ASP Conference Series, Vol. 199, 2000; J. H. Kastner, N. Soker, & S.A. Rappaport, eds
arxiv created 2000/02/14 · openalex publication_date 2000/02/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Images of Hubble 12 were obtained with the HST/NICMOS instrument in the F110W, F164N, and F166N filters of NIC1, and the F160W, F187N, F190N, F212N, F215N filters of NIC2. The images show the structure of the inner ``torus'' and lobes much clearer than previous ground-based images. In particular, the [Fe II] lobes are clearly resolved and shown to be distinct from the molecular hydrogen emission structures. Apparent changes in the inner ionized and neutral bipolar shell implies periodic mass loss or changes in stellar wind shape or direction. The molecular hydrogen in the ``eye'' is radiatively excited and shows a complex morphology that suggests that several mass ejection events are responsible for producing this structure. The position angle of the molecular hydrogen and [Fe II] lobes differ, indicating a possible precession of the ejection axis.