A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main-sequence stars with spectral types from solar to A0 show predictable changes with metallicity and detectable changes with evolution. Such stars populate the solar neighborhood and

Many barred galaxies show enhanced star formation activity in ring-like regions around their centres, at typical radii of 1-2 kpc. We show how kinematic (WHT TAURUS Fabry-Pérot velocity mapping) and imaging (CFHT near infrared adaptive optics) observational tests, combined with dynamical modelling, can help in unravelling the dynamics and star

Recent data colleted by the helioseismic experiments aboard SOHO have allowed the detection of low degree p-modes with lower and lower order, n. In particular, the GOLF experiment is currently able to identify unambiguously modes as low as n = 8 for l = 0, and l = 1 (e.g., ≍1.3 mHz). To detect p-modes with lower n (hence lower frequeny), where the

The study of δ Scuti stars in a cluster allows to consider that all the objects have the same age, chemical composition and distance. In addition to this, the parameters like metallicity or distance are better estimated for stars belonging to a cluster than for typical field stars. We consider here a set of four Delta Scuti stars in the Pleiades

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The necessity of finding a signal buried in noise is a common problem in astrophysics where noise limited observations are usually preceding interesting discoveries. In particular we are interested in the detection of p-mode oscillation frequencies of solar-like stars which, at least for the moment, have a very poor S/N ratio. In this work, it is