Beta Cephei stars have a simple structure: a convective core surrounded by a radiative envelope. It is therefore worth trying to describe beta Cephei stars with composite polytropes which are useful to retrieve structure parameters from frequency spectra. We show that the structure of beta Cephei models can relatively well be described with two

We present a detailed and uniform study of oxygen abundances in 155 solar type stars, 96 of which are planet hosts and 59 of which form part of a volume-limited comparison sample with no known planets. EW measurements were carried out for the [O I] 6300 Å line and the O I triplet, and spectral synthesis was performed for several OH lines. NLTE

We present high-resolution optical spectroscopy of the X-ray binary system SS433, obtained over a wide range of orbital phases. The spectra display numerous weak absorption features, and include the clearest example seen to date of those features (resembling a mid-A type supergiant spectrum), which have previously been associated with the mass

We have constructed a 3D photoionization model of a planetary nebula (PN) similar in structure to NGC 7009 with its outer pair of knots (also known as FLIERs - fast, low-ionization emission regions). The work is motivated by the fact that the strong [NII]λ6583 line emission from FLIERs in many PNe has been attributed to a significant local

We present preliminary results of a simultaneous X-ray/optical campaign of the prototypical LMXB Sco X-1 at 1 10 Hz time resolution. Lightcurves of the high excitation Bowen/HeII emission lines and a red continuum at λc ˜ 6000 Å were obtained through narrow interference filters with ULTRACAM, and these were cross-correlated with simultaneous RXTE X

We present a preliminary analysis of visible + infrared spectra (0.5 2.4 μm) of 17 asteroids in cometary orbits (ACOs), asteroidal objects with Tisserand parameter T 3. These objects are part of a larger database of ACOs observed with the Italian 3.56 m “Telescopio Nazionale Galileo” and the 2.5 m “Nordic Optical Telescope” at the “El Roque de los