Common wisdom identifies hydrogen lines in photoionized region with recombination lines. However, these lines can also be excited by different atomic mechanisms...
"Using high resolution spectroscopic data obtained with Magellan Inamori Kyocera Echelle (MIKE) at the Magellan telescope at Las Campanas Observatory it was...
Revealing the Mid-Infrared Emission Structure of IRAS 16594-4656 and IRAS 07027-7934
TIMMI2 diffraction-limited mid-infrared images of a multipolar proto-planetary nebula IRAS 16594-4656 and a young [WC] elliptical planetary nebula IRAS 07027...
We present a search for rings or arcs in the haloes of planetary nebulae (PNe). We discovered such structures in eight PNe, tripling the sample of PNe with...
Rotating Stars and the Formation of Bipolar Planetary Nebulae. II. Tidal Spin-up
We present new binary stellar evolution models that include the effects of tidal forces, rotation, and magnetic torques with the goal of testing planetary...
s-process enrichment in the planetary nebula NGC 3918. Results from deep echelle spectrophotometry
The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R ˜ 40 000) UVES (Ultraviolet-Visual Echelle Spectrograph)...
SALT reveals the barium central star of the planetary nebula Hen 2-39
Classical barium stars are binary systems which consist of a late-type giant enriched in carbon and slow neutron capture (s-process) elements and an evolved...
SAO 244567 - A post-AGB star which has turned into a planetary nebula within the last 40 years
SAO 244567 (Hen 1357 = CPD -59 deg 6926 = IRAS 17119-5926) is an IRAS source with far infrared colors and flux distribution similar to those of planetary...
SBS 1150+599A: An extremely oxygen-poor planetary nebula in the Galactic halo?
We report results of a spectrophotometric study of SBS 1150+599A and discuss the nature of this object based upon our data. Our study shows that SBS 1150+599A...