In this Letter, we discuss a method to conduct a quantitative study of the star formation history (SFH) of Local Group (LG) galaxies using Hubble Space Telescope (HST) data. This method has proved to be successful in the analysis of the SFH of the same kind of galaxies using ground-based observations. It is based on the comparison of observed CMDs

The spatial variation of physical quantities, such as the mass density, across solar atmospheric waveguides governs the timescales and spatial scales for wave damping and energy dissipation. The direct measurement of the spatial distribution of density, however, is difficult, and indirect seismology inversion methods have been suggested as an

An optically thick relativistic Keplerian accretion disk model is used to fit the broad component of the H-alpha, H-beta, and He I 5876 A emission line profiles of the active nucleus of NGC 985. A set of values of the relevant parameters is derived from the independent fits of the three lines. Those values are consistent for the lines examined and

The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside

A lunar eclipse offers a unique opportunity to investigate the terrestrial atmosphere. A recent work (Pallé et al. 2009) has published the Earth’s transmission spectrum from 0.36 to 2.40 μm obtained during the partial lunar eclipse of August 16th 2008. We have set out to interpret the measured spectrum, and assess to what extent the conclusions can

Asymptotic giant branch (AGB) stars are among the most important gas and dust polluters of the Universe. The latest AGB evolutionary models take into account dust production in the circumstellar envelope of these stars, starting from a detailed computation of the main physical processes and chemical surface variations occurring in this evolutionary