Infrared photometry in the J, H and K bands, performed on a sample of 33 blue stragglers (BS) belonging to 8 open clusters is presented. This photometry has been combined with published Johnson UBV photometry to search for possible cold companions among the BS, as expected for Case B close binary evolution. Probable binaries were identified by

Spectrophotometric observations in the optical and near-infrared of six giant H II regions in the high metallicity spiral galaxy M51 are presented. Five of the regions are located in the spiral arms, and the sixth one is very close to the nucleus. These observations and the application of adequate photo-ionization models allow the determination of

The identification of the Jovian frequency spectrum obtained by Schmider et al. (1990, 1991) is proposed from Doppler shift observations of the solar sodium D line reflected by the planet, as a signature of Jovian global-pressure modes. The spectrum, derived from 4 nights of observations, presents high-amplitude peaks whose origin in undoubtedly

PRESENTAMOS LOS RESULTADOS DE UN ESTUDIO COMBINADO EN EL OPTICO, INFRARROJO CERCANO E INFRARROJO LEJANO (IRAS) DE VEINTE REGIONES HII GALACTICAS DONDE YA EXISTIA INFORMACION BASTANTE COMPLETA EN ONDAS DE RADIO-MILIMETRICAS.LA MUESTRA DE REGIONES HII PRESENTA PROPIEDADES INFRARROJAS MUY BIEN DEFINIDAS: I) LA TEMPERATURA DE LOS GRANOS DE POLVO MAS

This paper discusses synthetic horizontal branches constructed from a grid of horizontal-branch (HB) evolutionary tracks with the alpha-elements enhanced by a factor of 5 with respect to the solar-scaled mixture and various surface helium and heavy-element abundances. The luminosity log L(3.83) and the luminosity-to-mass ratio A(3.83) of the ZAHB

An optically thick relativistic Keplerian accretion disk model is used to fit the broad component of the H-alpha, H-beta, and He I 5876 A emission line profiles of the active nucleus of NGC 985. A set of values of the relevant parameters is derived from the independent fits of the three lines. Those values are consistent for the lines examined and