2015/02/10 by Masaaki Otsuka, Siek Hyung, Akito Tajitsu · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Asymptotic giant branch #Excited state #Globular cluster #Halo #Line (geometry) #Nebula #Nucleosynthesis #Planetary nebula #Stars #Stellar nucleosynthesis #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/0067-0049/217/2/22
23 pages, 14 Figures and 20 Tables, accepted for publication in the Astrophysical Journal Supplement Series
arxiv created 2015/02/10 · openalex publication_date 2015/04/10 · arxiv updated 2015/06/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We report on an investigation of the extremely metal-poor and C-rich planetary nebula (PN) K648 in M15 using the UV to far-infrared data obtained using Subaru, the Hubble Space Telescope , the Far Ultraviolet Spectroscopic Explorer , Spitzer , and Herschel . We determined the nebular abundances of 10 elements. The enhancement of F ([F/H] = +0.96) is comparable to that of the halo PN BoBn1. The central stellar abundances of seven elements are determined. The stellar C/O ratio is similar to the nebular C/O ratios from recombination lines and from collisionally excited lines (CELs) within error, and the stellar Ne/O ratio is also close to the nebular CEL Ne/O ratio. We found evidence of carbonaceous dust grains and molecules including Class B 6–9 and 11.3 μ m polycyclic aromatic hydrocarbons and the broad 11 μ m feature. The profiles of these bands are similar to those of the C-rich halo PNe H4-1 and BoBn1. Based on the theoretical model, we determined the physical conditions of the gas and dust and their masses, i.e., 0.048 and 4.95 × 10 −7 , respectively. The observed chemical abundances and gas mass are in good agreement with an asymptotic giant branch nucleosynthesis model prediction for stars with an initial 1.25 plus a 2.0 × 10 −3 partial mixing zone (PMZ) and stars with an initial mass of 1.5 without a PMZ. The core mass of the central star is approximately 0.61–0.63 . K648 is therefore likely to have evolved from a progenitor that experienced coalescence or tidal disruption during the early stages of evolution, and became a ∼1.25–1.5 blue straggler.