Continuing our series of papers on the three-dimensional (3D) structure and accurate distances of planetary nebulae (PNe), we present here the results obtained for PN NGC 40. Using data from different sources and wavelengths, ...

Resonant features in low-energy photoionization cross sections are reported in coupled-channel calculations for O II including relativistic fine structure. The calculations reveal extensive near-threshold resonant structures ...

Molecular hydrogen emission is commonly observed in planetary nebulae. Images taken in infrared H(2) emission lines show that at least part of the molecular emission is produced inside the ionized region. In the best studied ...

Context. Detections of molecular lines, mainly from H-2 and CO, reveal molecular material in planetary nebulae. Observations of a variety of molecules suggest that the molecular composition in these objects differs from ...

Context. The analysis and interpretation of the H(2) line emission from planetary nebulae have been done in the literature by assuming that the molecule survives only in regions where the hydrogen is neutral, as in ...

Recent observations show the existence of an increasing number of collimated outflows ejected by young, low-mass stars which are embedded in H II regions. At distances of a few tens of au from the star, at least one lobe ...

Recent observations show the existence of an increasing number of collimated outflows ejected by young, low-mass stars which are embedded in H II regions. At distances of a few tens of au from the star, at least one lobe ...

High spectral resolution spectroscopy has proved to be very useful for the advancement of chemical abundances studies in photoionized nebulae, such as H II regions and planetary nebulae (PNe). Classical analyses make use ...

We present a new method for inferring the metallicity (Z) and ionization parameter (q) of H ii regions and star-forming galaxies using strong nebular emission lines (SELs). We use Bayesian inference to derive the joint and ...