Physical Conditions of the Planetary Nebula NGC 5315 Derived from VLT Echelle Observations and the t2 Problem

Peimbert, Manuel; Peimbert, Antonio; Ruiz, María Teresa; Esteban, César
Bibliographical reference

The Astrophysical Journal Supplement Series, Volume 150, Issue 2, pp. 431-454.

Advertised on:
2
2004
Number of authors
4
IAC number of authors
1
Citations
74
Refereed citations
59
Description
Echelle spectrophotometry of the planetary nebula NGC 5315 is presented. The data consist of VLT UVES observations in the 3100-10450 Å range. The intensities of 556 emission lines have been measured, including 508 identified permitted lines of H0, He0, C0, C+, N0, N+, N++, O0, O+, Ne0, Ne+, Mg+, Si+, S0, S+, S++, and Ar+. Electron temperatures and densities have been determined using many different line intensity ratios. The He+, C++, N++, O++, and Ne++ ionic abundances have been derived from recombination lines; these abundances are almost independent of the temperature structure of the nebula. Alternatively, abundances from collisionally excited lines have been derived for a large number of ions of different elements; these abundances depend strongly on the temperature structure. Accurate t2 values have been derived from the He I lines, and by comparing the O++ ionic abundances obtained from collisionally excited and recombination lines. The similarity between the widths and radial velocities of the O II and the [O III] lines rules out the presence of chemical abundance inhomogeneities in this object. The chemical composition of NGC 5315 is compared with those of the Orion nebula and the Sun. Based on observations collected at the European Southern Observatory, Chile, proposal number ESO 68.C-0149(A).