Deep narrow band CCD images in the Hα , [O Iii] lambda5007 Ä, [N Ii] lambda6584 Ä, and [S Ii] lambda6717 +31 Ä emission lines have been obtained for the planetary nebula M 2-48. The discovery of a pair of symmetric low-excitation bow-shocks, separated by 4', and forming a highly collimated bipolar outflow, is presented. The bow-shocks are emitting

SAX J1819.3-2525 is a nearby X-ray transient which exhibited a fast and large X-ray outburst on Sep. 15, 1999 (Smith et al. 1999). The Wide Field Cameras and the Narrow Field Instruments (NFI) on board BeppoSAX observed SAX J1819.3-2525 at various stages of its activity before that, in the spring and fall of 1999. The fluxes range between 0.012 and

We present time-series spectropolarimetric observations of sunspots in the Ca II infrared triplet lines, which show a periodic occurrence of anomalous, asymmetric, circular polarization profiles in the umbral chromosphere. The profiles may be caused by the periodic development of an unresolved atmospheric component in a downward flowing magnetized

We present time-series spectropolarimetric observations of sunspots in the Ca II infrared triplet lines, which show a periodic occurrence of anomalous, asymmetric, circular polarization profiles in the umbral chromosphere. The profiles may be caused by the periodic development of an unresolved atmospheric component in a downward flowing magnetized

Continuum subtracted dereddened images in several emission lines reveal the existence of an extended bipolar shell around η Carinae. It is best seen in the light of [ion{O}{3}]5007. The geometrical disposition and mass of the shell-between 5 and 7 Modot-suggest that it was produced by mass outflows from this star. The approximate size and dynamic

We present the results of a 2-D, two fluid (ions and neutrals) simulation of the ambipolar filamentation process, in which a magnetized, weakly ionized plasma is stirred by turbulence in the ambipolar frequency range. The higher turbulent velocity of the neutrals in the most ionized regions gives rise to a non-linear force driving them out of these