We have obtained intermediate resolution optical spectra of the black-hole candidate Nova Sco 1994 in June 1996, when the source was in an X-ray/optical active state (R~15.05). We measure the radial velocity curve of the secondary star and obtain a semi-amplitude of 279+/-10 km s-1 a value which is 30 per cent larger than the value obtained when

Bright circumstellar nebulae around massive stars are potentially useful to derive time-dependent mass-loss rates and hence constrain the evolution of the central stars. A key case in this context is the relatively young ejection-type nebula M1-67 around the runaway Population I Wolf-Rayet star WR 124 (=209 BAC), which exhibits a WN 8 spectrum

We analysed high resolution spectra of Galactic O-type stars from the far-UV to the optical. We combined spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE) in the range 905-1187Å, IUE or HST archive spectra (1150-3300Å), and optical blue and Hα spectra from the La Palma INT. The spectra were analysed with line-blanketed, hydrodynamic

Sunrise is a solar telescope with an aperture of 1 m, and is dedicated for spectropolarimetric measurements in the visible and the near UV. The total wavelength range is 200 to 1000 nm for narrowband imaging and diagnostic spectroscopy. Sunrise is planned as a stratospheric long-duration balloon mission with a first flight in 2006

A 2-D global hybrid simulation is carried out to study the structure of the dayside magnetopause in the noon-midnight meridian plane associated with magnetic reconnection. In the simulation the bow shock, magnetosheath, and magnetopause are formed self-consistently by supersonic solar wind passing the geomagnetic field. The reconnection events at

We present a multi-wavelength study of the gas dynamics and star formation in the grand-design spiral galaxy NGC 5248, illustrating how coupled dynamical mechanisms can generate spiral structures from tens of kpc to hundreds of pc, drive disk evolution, and fuel star formation on progressively smaller scales. Although to date NGC 5248 has been