Z-bump opacities are known to excite radial pulsations in helium stars with 102~

Recent observations at the NOT telescope clearly show that PG 1618+563 is a new member of the EC14026 class of sdB pulsating stars (Kilkenny et al. 1997, O'Donoghue et al. 1999). The very good quality of the non-filtered data allows to detect an amplitude modulation effect with a beat period of about 1.2 hours, which is consistent with the presence

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The reliability of oxygen abundances derived from OH UV lines in metal-poor dwarf stars is discussed in the light of the stellar parameters adopted and the tools employed. These abundances appear to be in very good agreement with the abundances derived from other indicators in unevolved stars when consistent analyses are made and accurate stellar

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Temporal variations of a solar pore were observed at the ground based Vacuum Tower Telescope (VTT) on Tenerife and with the satellite TRACE. At the VTT Stokes I and V of the iron line at 1.56 mu m, originating in the deep photosphere, was measured. TRACE delivered UV images at 170 nm which show chromospheric continuum. In a part of the pore we find