Bibcode
Sherrard, C. G.; Sterling, Nicholas C.; Dinerstein, Harriet L.; Madonna, S.; Mashburn, Amanda
Referencia bibliográfica
American Astronomical Society, AAS Meeting #230, id.318.11
Fecha de publicación:
6
2017
Número de citas
0
Número de citas referidas
0
Descripción
We present an abundance analysis of 17 planetary nebulae (PNe) observed
with the 2D-coudé echelle spectrograph on the 2.7-m Harlan J.
Smith telescope at McDonald Observatory. The spectra cover the
wavelength range 3600--10,400 Å at a resolution R = 36,700, and
are the first high-resolution optical spectra for many objects in our
sample. The number of emission lines detected in individual nebulae
range from ~125 to over 600. We derive temperatures, densities, and
abundances from collisionally-excited lines using the PyNeb package
(Luridiana et al. 2015, A&A, 573, A42) and the ionization correction
factor scheme of Delgado-Inglada et al. (2014, MNRAS, 440, 536). The
abundances of light elements agree with previous estimates for most of
the PNe. Several objects exhibit emission lines of refractory elements
such as K and Fe, and neutron-capture elements that can be enriched by
the s-process. We find that K and Fe are depleted relative to solar by
~0.3--0.7~dex and 1-2 dex, respectively, and find evidence for s-process
enrichments in 10 objects. Several objects in our sample exhibit C, N,
and O recombination lines that are useful for abundance determinations.
These transitions are used to compute abundance discrepancy factors
(ADFs), the ratio of ionic abundances derived from permitted lines to
those from collisionally-excited transitions. We explore relations among
depletion factors, ADFs, s-process enrichment factors, and other nebular
stellar and nebular properties. We acknowledge support from NSF awards
AST-901432 and AST-0708429.