Abundances in the Planetary Nebula IC 5217

Abstract

High-resolution optical wavelength spectroscopic data were secured in the optical wavelengths, 3700È 10050 for the planetary nebula IC 5217 with the Hamilton Echelle Spectrograph at Lick Observatory. A , These optical spectra have been analyzed along with the near-UV and UV archive data. Diagnostic analyses indicate a nebular physical condition with electron temperature of about 10,700 K (from the [O III] lines) and the density of cm~1. Ionic concentrations have been derived with the repre-N v \ 5000 sentative diagnostics, and with the aid of a photoionization model construction, we derived the elemental abundances. Contrary to the previous studies found in the literature, He and C appear to be depleted compared to the average planetary nebula and to the Sun (and S marginally so), while the remaining elements appear to be close to the average value. IC 5217 may have evolved from an O-rich progenitor, and the central star temperature of IC 5217 is likely to be 92,000 K.

Study of electron density in planetary nebulae

“…The data used were taken from the electronic emissionline catalogue for planetary nebulae by Kaler et al (1997), from Kingsburgh & English (1992) and from the spectral survey of high surface brightness planetaries by Hyung, Aller, Feibelman and collaborators (Aller & Hyung 1995;Aller et al 1996;Feibelman et al 1994Feibelman et al , 1996Hyung 1994;Hyung & Aller 1995a,b, 1996, 1997a,b, 1998Hyung et al 1993Hyung et al , 1994aHyung et al ,b,c, 1995Hyung et al , 1997Hyung et al , 1999aHyung et al ,b, 2000Hyung et al , 2001Keyes et al 1990). Instead of comparing directly the derived densities, as has been done by other authors, what implies in discarding all line ratios close or beyond the saturation limits at low and high densities, we have compared the line ratios themselves with one another.…”

IC 5217 as a double-shell, point-symmetric planetary nebula with a very narrow waist

“…Assuming a distance of 2.5 kpc (Hyung et al 2001), T e = 10 4 K and following the formulation by Mezger & Henderson (1967) for optically thin emission, we can obtain several physical parameters for IC 5217. By considering a sphere of radius 2.…”

“…IC 5217 was included in the target list. It is a medium excitation PN (Aller & Liller 1968) with a relatively faint (V 15.5) central star that presents WR characteristics and a T eff ∼ 95 000 K (Hyung et al 2001). After being considered as an elongated PN with the major axis along the North−South direction (Curtis 1918), the images by Balick (1987) have shown that IC 5217 presents faint open bipolar lobes oriented East−West and that the previously identified elongated structure can be better interpreted as a bright equatorial ring seen almost edge-on.…”

A Reexamination of Electron Density Diagnostics for Ionized Gaseous Nebulae

“…On the other hand, a very different result was obtained by Meatheringham & Dopita (1991) who found that for a sample of 44 PNe in the Magellanic Clouds, [S ] densities were systematically lower than those determined from the [O ] doublet ratio. Using high resolution spectroscopic data obtained with an echelle spectrograph, mostly by the group led by Aller Aller et al 1996;Feibelman et al 1994Feibelman et al , 1996Hyung 1994;Hyung & Aller 1995a,b, 1996, 1997a,b, 1998Hyung et al 1993Hyung et al , 1994aHyung et al ,b,c, 1995Hyung et al , 1997Hyung et al , 1999aHyung et al ,b, 2000Hyung et al , 2001Keyes et al 1990;Keenan et al 1993Keenan et al , 1996Keenan et al , 1997 they determined simultaneously electron densities and temperatures using a number of plasma diagnostic lines in the optical and ultraviolet and found that overall the data yielded compatible and consistent results. More recently, Copetti & Writzl (2002), using data published in the literature, compared the observed line ratios for a number of density-diagnostics, instead of densities deduced from them, thus avoiding discarding measurements that yield ratios close to or beyond the the low-or high-N e limits.…”