Bibcode
DOI
Maran, S. P.; Stecher, T. P.; Wood, P. R.; Meatheringham, S. J.; Ford, H. C.; Harrington, J. P.; Bohlin, R. C.; Dopita, M. A.; Vassiliadis, E.
Referencia bibliográfica
Astrophysical Journal Supplement, v.114, p.237
Fecha de publicación:
2
1998
Número de citas
12
Número de citas referidas
9
Descripción
The Faint Object Spectrograph on board the Hubble Space Telescope (HST)
is used to obtain spectra in the wavelength range lambda lambda
1150-4800 of three planetary nebulae in the Small Magellanic Cloud and
10 planetary nebulae in the Large Magellanic Cloud. This sample extends
the sample of 12 objects previously observed with HST and reported in
the third paper of this series. Observed and dereddened emission-line
fluxes are presented. Reddening estimates from the He II lambda 1640/
lambda 4686 flux ratio are generally up to 0.2 dex lower than the
reddening derived from the Balmer decrement. Nebular temperatures are
estimated from the N+ lambda lambda 2138, 2142/ lambda lambda 6548, 6583
flux ratio. Nebular densities are calculated from the O IV] complex at
lambda 1400, the N IV] lambda lambda 1483, 1487 doublet, and the Si III]
lambda lambda 1883, 1892 doublet. Densities calculated using the oxygen
lines are comparable to those determined from the optical lines.
Densities calculated from the nitrogen lines show a scatter of over 3
dex, which is relatively large compared to the optically derived
densities. Three of the five densities derived from the silicon lines
are greater than 10,000 cm-3. The C+2/O+2, Si+2/C+2, and N+2/O+2 ionic
abundance ratios are calculated using the available ultraviolet emission
features. The C/O and N/O ratios are anticorrelated, which supports the
premise that third dredge-up has taken place during the asymptotic giant
branch phase. In contrast to the third paper in this series, type I
classification does not imply the presence of Si III] emission. Three
objects show P Cygni-like line profiles at C IV lambda lambda 1548,
1551, indicative of stellar winds.