Maralinga is an anomalous CK4 carbonaceous chondrite which contains numerous Ca-, Al-rich inclusions (CAI's) unlike the other members of the CK group. These CAI's are characterized by abundant green hercynitic spinel intergrown with plagioclase and high-Ca clinopyroxene, and a total lack of melilite. Instrumental Neutron Activation Analysis (INAA)

The results of detailed, high-spatial-resolution spectroscopy for a sample of eleven nebulae surrounding Wolf-Rayet stars: S308, NGC 2359, NGC 3199, Anon (MR 26), RCW 78, RCW 104, G 2.4+1.4, M 1-67, L 69.8+1.74, Anon (MR 100), and NGC 6888, are presented. The study of the ionization structure, using diagnostic diagrams, indicates that

ESTE TRABAJO SE ENMARCA EN EL AMBITO DE NUEVOS METODOS TECNICOS APLICADOS A LA ASTRONOMIA, Y POR TANTO CON UNA CONSIDERABLE POTENCIALIDAD. EL NEXO DE UNION SON LAS REDES DE NEURONAS ARTIFICIALES Y CONSISTE BASICAMENTE EN EL ESTUDIO DE SU APLICABILIDAD A TRES PROBLEMATICAS DIFERENTES CON UTILIDAD EN EL CAMPO DE LA ASTRONOMIA: UN METODO PARA

We report how the action of radiation forces on small solid particles in a circumstellar disk could induce a suitable mechanism for orbital migration of protoplanets. Since the ratio of radiation-to-gravitational forces acting on a particle depends on its physical and chemical properties, different particles following the same trajectory move with

The main problem in using the inverse Abel transform of an experimentally observed function is that it involves numerical differentiation, which amplifies the errors affecting the measurements. This difficulty can be overcome by using spectral expansion methods, with coefficients obtainable through a numerical integration. The inaccuracy of the

The amount of data produced by large observational facilities and space missions has led to the archiving and on-line accessibility of much of these data, available to the entire astronomical community, and allowing a much wider multi-frequency approach of astronomical research than previously possible. Here I intend to draw attention to these