By a large number of high-precision photoelectric photometry data obtained in three sites, making use of the method of Fourier Period Analysis, the multiple frequencies of HD213534 have been obtained. Five frequencies have been definitely detected. Through the discussion of the pulsation modes of the star, we tended to believe that it is a multiple

The galaxy NGC 5506 hosts an active nucleus, that presents characteristics that are intermediate between Sy1 and Sy2. We discuss long slit spectra of NGC 5506 in the ranges 4675-5475 A and 6300-7125 A, that were obtained at three different position angles, in Apr. 1991 at the WHT 4.2 m telescope. The peculiar kinematics of the emitting gas has

The onset of forbidden line emission in the spectrum of a proto-planetary nebula has been detected for the first time in the lapse of only two years. IRAS 06562-0337 was first observed in December 1987 and October 1988, showing only the Balmer lines in emission. A third spectrum obtained in February 1990 shows a quite different appearance, with

EL OBJETIVO DE ESTA TESIS ES EL ESTUDIO DE LOS CUATRO OBJETOS TIPO AM CVN CONOCIDOS (AM CVN, GP COM, CR BOO Y V803 CEN). EN LA MEMORIA SE INCLUYE UNA EXTENSA REVISION DE LA BIBLIOGRAFIA RELEVANTE, QUE MUESTRA LA NECESIDAD DE REALIZAR NUEVAS OBSERVACIONES Y COORDINAR EL ESTUDIO EN DIFERENTES LONGITUDES DE ONDA, PARA DAR RESPUESTA A LOS INTERROGANTES

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