The three helioseismology instruments aboard SOHO observe solar p modes in velocity (GOLF and MDI) and in intensity (VIRGO and MDI). Time series of two months duration are compared and confirm that the instruments indeed observe the same Sun to a high degree of precision. Power spectra of 108 days are compared showing systematic differences between

We have obtained medium resolution spectra of the neutron star X-ray transient Aql X-1 during quiescence. We determine the spectral type of the companion star to be K1 and also estimate its rotation speed to be 62^+30^_-20_km/s. By measuring the width of the Hα emission line profile of the accretion disc, we estimate the binary inclination to ~50°

The Antlia dwarf galaxy, recently found to be a possible local Group member, is analyzed using VI photometry. The galaxy is resolved into a large number of stars and although the galaxy is intrinsically faint and of low surface brightness, its stellar populations reveal characteristics more typical of faint star-forming dIrs rather than dEs

We present an extensive study of lithium abundances in dwarf components of chromospherically active binary stars (CABS). Since most of these binaries have known radii, masses and ages, this kind of data is especially useful for comparisons with theoretical models which try to explain the Li depletion phenomenon. We show that a significant part of

In the context of a more extensive project, a study of the structural components of the barred spiral galaxy NGC 5850 is presented here, using U, B, V, R, and I photometry. After subtracting a bulge+disk model from the observed image, we obtain the bars, rings and other non-axisymmetric structures. We fit two-dimensional analytic functions for each

An analysis of the 5 minute oscillation in the solar photosphere has been carried out using an inversion of the radiative transfer equation applied to a time-series of K I lambda 7699 line spectra with a 5" x 5" window at disk center. A thorough discussion of the inversion conditions, with special emphasis on the LTE approach and a careful error