Open AccessSpectroscopy of six highly evolved Abell planetary nebulae
Author(s) -
Phillips J. P.,
Cuesta Luis,
Kemp S. N.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.08664.x
Subject(s) - physics , astrophysics , planetary nebula , spectroscopy , emission spectrum , line (geometry) , radius , astronomy , nebula , absorption spectroscopy , stars , spectral line , optics , geometry , mathematics , computer security , computer science
We have undertaken visual spectroscopy of the highly evolved planetary nebulae (PNe) A8, A13, A62, A72, A78 and A83 over a wavelength range 4330 < λ < 6830 Å . This permits us to specify relative line intensities in various sectors of the nebular shells, and to investigate the variation of emission as a function of radius. We determine that the spectrum of the central star of A78 has varied appreciably over a period of 25 yr. There is now evidence for strong P Cygni absorption in the λ4589 and λ5412 transitions of He ii , implying terminal velocities of the order of V ∞ ≅ 3.83 × 10 3 km s −1 . We also note that the emission‐line profiles of the sources can be used to investigate their intrinsic emission structures. We find that most PNe show appreciable levels of emission throughout their volumes; only one source (A13) possesses a thin‐shell structure. Such results are in conformity with evolutionary theory, and probably reflect the consequences of adiabatic cooling in highly evolved outflows.