The evolutionary scenario concerning the production and the cooling of He white dwarfs is revisited and discussed. We show that, for a given star metallicity, the minimum mass of H-rich envelopes able to support a red giant structure linearly decreases when the logarithm of the red giant luminosity increases. Increasing the metallicity the mass of

Sine 1984, simultaneous observations of irradiance and velocity solar acoustic modes, have been carried out by several authors in order to measure the phase difference between irradiance and velocity modes. Following the earliest observations with a stratospheric balloon (Frolich and van Der Raay, 1984), a two ground-based stations (Tenerife and

In the (logR_e_, μ_e_) plane defined by the logarithm of the effective radius and the effective surface brightness, elliptical galaxies that are members of Hickson's compact groups turn out to belong to the bright family, thus suggesting that most of them have likely experiences subtantial secondary evolution.

A reminder of the various factors that affect the central wavelength and bandpass of interference filters.

We present an alternative interpretation of the quiescent optical light curve of GS2000 +25 published by Chevalier & Ilovaisky, and show that the modulation can be explained by a single periodicity. Using a method that is independent of the characteristics of the modulation of the light curve, we obtain an alternative value for the orbital period

Infrared Astronomy Satellite (IRAS) 17423-1755 has been identified as a BQ() star. Its more remarkable observed features are large radial velocities, huge line widths and double-peaked profiles arising from its knots, and a high-velocity jet. Ejection velocity can account for the observational properties detected.