2005/03/03 by Simón Casassus, S. Casassus, P. J. Storey +2
Physics and Astronomy · #Angular momentum #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atomic and Molecular Physics #Atomic physics #Emission spectrum #Hyperfine structure #Line (geometry) #Physics #Planetary nebula #Quadrupole #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2005.08994.x
published as Mon.Not.Roy.Astron.Soc. 359 (2005) 1386-1392 · 7 pages, 4 figure, accepted for publication in MNRAS
arxiv created 2005/03/03 · openalex publication_date 2005/05/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The core of planetary nebula NGC 6302 is filled with high-excitation photoionized gas at low expansion velocities. It represents a unique astrophysical situation in which to search for hyperfine structure (HFS) in coronal emission lines from highly ionized species. HFS is otherwise blended by thermal or velocity broadening. Spectra containing [Al vi] 3.66 μm 3P2 ← 3P1, obtained with Phoenix on Gemini South at resolving powers of up to 75 000, resolve the line into five hyperfine components separated by 20–60 km s−1 as a result of the coupling of the I = 5/2 nuclear spin of 27Al with the total electronic angular momentum J. The isotope 26Al has a different nuclear spin of I = 5, and a different HFS, which allows us to place a 3σ upper limit on the 26Al/27Al abundance ratio of 1/33. We measure the HFS magnetic dipole coupling constants for [Al vi], and provide the first estimates of the electric quadrupole HFS coupling constants obtained through astronomical observations of an atomic transition.