We present accurate relative ages for a sample of 55 Galactic globular clusters. The ages have been obtained by measuring the difference between the horizontal branch and the turnoff in two internally photometrically homogeneous databases. The mutual consistency of the two data sets has been assessed by comparing the ages of 16 globular clusters in

We explore the formation and evolution of hydrogen-deficient post-AGB white dwarf stars by computing the complete evolution of an initially 2.7 Msun star from the ZAMS through the thermally pulsing and mass-loss phases, the born-again stage to the white dwarf stage. A time-dependent scheme for the simultaneous treatment of abundance changes caused

The destructive 1980 Campania-Lucania earthquake was a complex event, consisting of at least three subevents. While the main features of the first (0 s) and of the last (40 s) subevents are widely accepted, the second subevent (20 s) is still controversial. Fault geometries are here determined from levelling data, using a global minimization

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En este trabajo se realiza la implementación del método de extinción- distancia para determinar distancias a nebulosas planetarias, utilizando la clasificación espectral que realiza un sistema de redes neuronales artificiales. La aplicación del método mencionado exige la clasificación espectral de un numeroso grupo de estrellas de campo cercanas a

We present the transient nature of INTEGRAL source IGR J17285 2922, identified from a single period of activity during an IBIS/ISGRI Galactic Centre Deep Exposure in September 2003. The source has a maximum detection significance of 14σ in the 20 100 keV energy range and exhibits a flux of 6.5 mCrab before it moves out of the ISGRI field of view