Based on high quality observations of multiplet V1 of O II and the NLTE atomic computations for O II we study the density and temperature of a sample of PNe. We...

We determine the physical conditions in NGC 6543, obtaining two different estimates of the electron temperature (T[e]) and one estimate of the electron density...

We revise the physical conditions in the O++ zone of the planetary nebula NGC 6543, obtaining two different estimates of the electron temperature (Te) and one...

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...

The Owl Nebula is a triple-shell planetary nebula with the outermost shell being a faint bow-shaped halo. We have obtained deep narrowband images and high...

Late stages of stellar evolution are characterized by copious mass-loss events whose signature is the formation of circumstellar envelopes (CSE). Planck multi...

This paper presents a homogeneous study of abundances in a sample of 79 northern Galactic planetary nebulae (PNe) whose morphological classes have been...

Planetary nebulae (PNe) have been used to trace the chemical evolution of galaxies, not only in the Milky Way (Esteban & Peimbert 1995 and references therein)...

In a search for emission line objects made in a southern region of M 33 using narrow band filters centered on [O III], Hα and adjacent continua, we detect some...