La observación del cometa Halley desde el IAR

El cometa Halley fue observado con el radiotelescopio del IAR, entre el 6 de febrero y el 1º de mayo de 1986, en la línea de 1667 MHz (λ=18 cm) del radical OH. La línea fue detectada en absorción entre el 23 de marzo y el 23 de abril. No se observaron asimetrías significativas en los perfiles. El número total de moléculas de OH, calculado en base a los perfiles observados y al modelo utilizado por Scloerb y Gerard (1985), muestra variaciones semi-periódicas con relaciones entre máximos y mínimos del orden de 1,7 y su valor medio es 2,5 veces mayor que el valor predicho por dichos autores.The Halley Comet was observed with the IAR radio telescope, between the 6th of February and the 1st of May, 1986 in the OH-1667 MHz line. The line was detected in absorption between the 23rd of March and the 23rd of April. No significative asymmetries were observed. The total number of OH molecules, as derived from the profiles and the model used by Schloerb and Gerard (1985), shows quasi-periodic varlations wlth maximum-to-minimum ratios of about 1.7 and its average is about 2.5 times larger than the predicted valué.Asociación Argentina de Astronomí

On the distance and structure of W80

The continuum radiation of the Galactic region located at l = 85°, b = -0.5° is well defined by its 11 cm emission. The region, extended 3° in diameter, is cataloged as W80, and its optical images show the North America and Pelican Nebulae complexes. In this paper we present new distance measurements and physical parameters obtained from radio recombination line observations at a frequency near 1.4 GHz. Four structures are identified in the region under study: a near structure is located at a distance of about 0.7 kpc, another structure lies on the east side of W80 at a distance of 1.7 kpc, there is a concentration of ionized gas on the west side at a distance of 2.7 kpc, and a fourth structure is found further away at 3.3 kpc, which does not seem to belong to the W80 complex. The results are presented using the (X, Y, Z)-coordinates of the Galactic plane. The model used assumes a constant electron temperature Te = 6800 K and also assumes homogeneity. Our results seem to indicate that the ionized hydrogen of W80 spreads along the line of sight instead of clumping at one distance. We obtain values of the electron density and the ionization parameter between ne = 5 and 16 cm-3 and U = 51 and 110 cm-2 pc, respectively.Fil: Cersósimo, Juan Carlos. Universidad de Puerto Rico; Puerto RicoFil: Muller, R. J.. Universidad de Puerto Rico; Puerto RicoFil: Figueroa Vélez, S.. Universidad de Puerto Rico; Puerto RicoFil: Santiago Figueroa, N.. Universidad de Puerto Rico; Puerto RicoFil: Baez, P.. Universidad de Puerto Rico; Puerto RicoFil: Testori, Juan Carlos. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; Argentin