Time-resolved medium resolution spectroscopy is presented for six cataclysmic variables discovered by the Sloan Digital Sky Survey. For four of these systems the data are extensive enough to determine orbital periods from measurements of the radial velocity motion of the Balmer emission lines. For one of the systems we also present time-resolved

Extinction due to intergalactic grey dust has been proposed as an alternative to accelerated expansion to account for the dimming of SnIa fluxes beyond z ≃ 0.5. The "replenishing" grey dust model, although fitting the observational data, does not seem to be based on physical assumptions. For this reason, in this paper we propose a new grey dust

Measuring the population of obscured quasars is one of the key issues in understanding the evolution of active galactic nuclei (AGNs). With a redshift completeness of 99%, the X-ray sources detected in the Chandra Deep Field South (CDF-S) provide the best sample for this issue. In this paper, we study the population of obscured quasars in CDF-S by

We present evidence that recently identified massive rubidium-rich AGB stars also played an important role as sources of certain long-lived and short-lived radionuclides to the early solar nebula, just during early stages of meteorite formation.

Magnetic fields are an important but largely unknown ingredient of planetary nebulae. They have been detected in oxygen-rich asymptotic giant branch (AGB) and post-AGB stars, and may play a role in the shaping of their nebulae. Here we present SCUBA submillimetre polarimetric observations of four bipolar planetary nebulae and post-AGB stars

The reduced photometric data of HD 172189 are provided. The original data were obtained from the XIII STEPHI campaign carried out between 7-28 June 2004 by three observatories: Observatorio del Teide (Izana, Tenerife, Spain), Observatorio Astronomico Nacional de San Pedro Martir (Baja California, Mexico) and Xinglong Station of the Beijing