The physics of infrared emission processes is examined, taking into account black body radiation, radiation from dust particles, thermal plasma emission, nonthermal plasma emission (synchrotron), line emission from gaseous nebulae, and line emission from molecular clouds. Late-type stars and mass loss are considered along with early-type stars

LAS MANCHAS SOLARES CONSTAN DE UNA ZONA CENTRAL OSCURA LLAMADA SOMBRA Y OTRA ZONA ENVOLVENTE DE ESTRUCTURA FILAMENTARIA EN DISPOSICION RADIAL DENOMINADA PENUMBRA . EL OBJETO DE ESTE TRABAJO HA SIDO ESTUDIAR LA DISTRIBUCION DE BRILLO EN LA PENUMBRA A PARTIR DE LAS IMAGENES FOTOGRAFIADAS DURANTE UN ECLIPSE DE SOL. EN UNA PRIMERA PARTE EXPONEMOS UN

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Spectral indices (delta m2100 and delta m1500) for 32 O-type stars with known spectral class and reddening are plotted versus log of effective temperature. The delta m2100 indices are considered to be almost luminosity-independent, while evidence of a well-established relationship between observed spectral indices and empirical temperatures appears

The software package ELSPEC/1 written at Trieste Astronomical Observatory for the automatic reduction of spectrograms digitized by a PDS 1010A microdensitometer is described and an example of the results obtained is shown. The package accepts spectrograms in the format of the Observatoire de Hauts Provence and operates on a HP 2100A minicomputer.