We derive a self-consistent set of atmospheric parameters and abundances of 17 elements for the red giant star Arcturus: T eff = 4286 ± 30 K, log g = 1.66 ± 0.05, and [Fe/H] = -0.52 ± 0.04. The effective temperature was determined using model atmosphere fits to the observed spectral energy distribution from the blue to the mid-infrared (0.44 to 10

We have analyzed six OB supergiants and one giant covering spectral types from O3 to B1 in the Galactic OB association Cyg OB2 by means of an updated version of FASTWIND (Santolaya-Rey et al. cite{sph97}) that includes an approximate treatment of metal line blocking and blanketing. This large coverage in spectral type allows us to derive a new

The Hipparcos mission has made it possible to constrain the positions of nearby field stars in the colour-magnitude diagram with very high accuracy. These positions can be compared with the predictions of stellar evolutionary calculations to provide information on the basic parameters of the stars: masses, radii, effective temperatures, ages, and

High-resolution spectra of a sample of all known stars more luminous than MV=+6.5 and closer than 15 parsecs are being analyzed spectroscopically in order to derive their effective temperatures and surface gravities. These spectra are taken from the database of "A Spectroscopic Survey of Stars in the Solar Neighborhood". The analysis utilizes a

The ratios between the amplitudes of p-modes measured simultaneously in the Na and K resonance lines are compared with the expected ratios for adiabatic waves at two different levels in the atmosphere. The results agree within errors with the energy decaying solution for the waves at the photosphere.

We present optical and near-infrared colour maps of the central regions of bulges of S0 and spiral galaxies obtained with WFPC2 and NICMOS on the Hubble Space Telescope (HST). By combined use of HST and ground-based data, the colour information spans a region from a few tens of pc to a few kpc. In almost all galaxies, the colour profiles in the