We have tested current models for the atmospheres (including photosphere and low chromosphere) of late-type stars using the D resonance lines of neutral sodium as a diagnostic. To this end, we have measured the equivalent widths of the D lines for a sample of 39 dwarf and 45 giant late-type stars observed with high spectral resolution. We

From the peak of a gravitational microlensing high-magnification event in the A component of QSO 2237+0305, which was accurately monitored by the Gravitational Lenses International Time Project collaboration, we derived new information on the nature and size of the optical V-band and R-band sources in the distant quasar. If the microlensing peak is

We present a gallery with some of the most interesting microstructures of low-ionization found in planetary nebulae (PNe). A rich zoo of knots, filaments, jets and jet-like systems are introduced, together with their morphological and kinematic properties. We briefly compare the predictions of the theoretical mechanisms for their formation with the

The starburst phenomenon can shape the evolution of the host galaxy and the surrounding intergalactic medium. The extent of the evolutionary impact is partly determined by the duration of the starburst, which has a direct correlation with both the amount of stellar feedback and the development of galactic winds, particularly for smaller mass dwarf

Near-Infrared J H K images are presented for a small sample of HII galaxies observed at UKIRT. Based on NIR colours, comparison with the stellar population models allowed us to further discuss the history of star formation in these bursting dwarf galaxies. Light and colour profiles are used to investigate their possible links with other types of

We observed the neutron star transient SAX J1810.8-2609 with Swift-XRT on November 3rd and 5th, in order to follow its way to quiescence. The source was not detected during the individual ~1.6 ksec and ~1.9 ksec observations. We place 95% upper limits on its 0.5-10 keV unabsorbed flux of [3.4-4.2]E-13 erg/cm2/s (November 3rd.) and [2.9-3.6]E-13 erg