Bibcode
Kwitter, K. B.; Dufour, Reginald J.; Shaw, Richard A.; Henry, Richard B. C.; Balick, Bruce; Corradi, R. L. M.
Referencia bibliográfica
American Astronomical Society, AAS Meeting #224, #121.09
Advertised on:
6
2014
Número de citas
0
Número de citas referidas
0
Descripción
In HST Cycle 19 we observed 10 Milky Way planetary nebulae (PNe) from
1150-10270Å with STIS to obtain accurate abundances of
carbon, nitrogen and oxygen. The ultimate goal of the project is to
assess carbon production in the low-to-intermediate-mass (LIMS)
progenitors of PNe with near-solar metallicity 0.5-1.2 x solar), but
varying N/O 0.1-3), comparing observational data with theoretical
models of carbon yields. Seven of our objects had data of sufficient
quality to allow good empirical abundance determinations: IC2165,
IC3568, NGC2440, NGC3242, NGC5315, NGC5882, and NGC7662. Each PN was
observed with seven grating setting combinations with identical slit
positions and slit sizes across the entire UV-optical spectral region.
We created one-dimensional spectra from the two-dimensional STIS
spectral images, taking care to extract the identical spatial region
from each spectrum for a given object. This was done to produce
one-dimensional spectral lines integrated along the slit, resulting in
the highest signal-to-noise measurements for analysis. We measured line
fluxes with IRAF and calculated nebular diagnostics and abundances with
ELSA. The crucial value in using STIS is the ability to observe the
ultraviolet lines of important CNO ions with higher signal-to-noise than
in previous studies. In all objects we detected lines of C+,
C+2, and C+3. We also detected N+ and
N+4 in all objects; in four of the seven we also detected
N+2 and N+3. We will present these data and
compare them with previous determinations and analyses (largely from the
old IUE datasets and studies). We gratefully acknowledge support from
HST and from Williams College.