Metal opacity shapes the near-UV spectrum of late-type stars, which dominate intermediate and old stellar populations. Learning the details of how metal opacity blocks the light in this spectral region is of capital importance to understanding the energy balance in the atmosphere of these stars and, ultimately, building reliable models to interpret

We consider deterministic chaotic models of vacuum fluctuations on a small (quantum gravity) scale. As a suitable small-scale dynamics, nonlinear versions of strings, so-called `chaotic strings' are introduced. These can be used to provide the `noise' for second quantization of ordinary strings via the Parisi- Wu approach of stochastic quantization

We have identified two late M dwarfs within 10 pc of the Sun, by cross-correlating the Luyten NLTT catalogue of stars with proper motions larger than 0.18 arcsec/yr, with objects lacking optical identification in the 2MASS data base. The 2MASS photometry was then combined with improved optical photometry obtained from the SuperCOSMOS Sky Surveys

We present high- and intermediate-resolution spectroscopy of the X-ray nova Centaurus X-4 during its quiescent phase. Our analysis of the absorption features supports a K3-K5 V spectral classification for the companion star, which contributes ~=75 per cent of the total flux at Hα. Using the high-resolution spectra we have measured the rotational

Quantitative structural analysis of the galaxies present in the Hawaiian Deep Fields SSA13 and SSA22 is reported. The structural parameters of the galaxies have been obtained automatically by fitting a two-component model (Sérsic r1/n bulge and exponential disc) to the surface brightness of the galaxies. The galaxies were classified on the basis of

Photometry of a large field around the young globular cluster Palomar 12 has revealed the main sequence of a low surface brightness stellar system. This main sequence is indicative of a stellar population that varies significantly in metallicity and/or age but in the mean is more metal-poor than Pal 12. Under different assumptions for the