2013/07/26 by M. A. Guerrero, J. A. Toalá, Juan J. Medina +5 · 32 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Collimated light #Doubly ionized oxygen #Emission spectrum #Geometry #Laser #Line (geometry) #Optics #Physics #Planetary nebula #Shock (circulatory) #Shock wave #Spectral line #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201321786
published in Astronomy and Astrophysics 557, A121 (EDP Sciences) · 13 pages, 9 figures, 3 tables; To appear in Astronomy & Astrophysics
openalex publication_date 2013/07/26 · arxiv created 2013/07/30 · arxiv updated 2015/06/16 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O iii]/Hα. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrow-band [O iii] and Hα images of PNe available in the HST archive to build their [O iii]/Hα ratio maps and to search for regions where this ratio is enhanced. Regions with enhanced [O iii]/Hα emission ratio can be ascribed to two different types of morphological structures: bow-shock structures produced by fast collimated outflows and thin skins enveloping expanding nebular shells. Both collimated outflows and expanding shells are therefore confirmed to generate shocks in PNe. We also find regions with depressed values of the [O iii]/Hα ratio which are found mostly around density bounded PNe, where the local contribution of [N ii] emission into the F656N Hα filter cannot be neglected.