Evolution of maser emission in the direction of the semiregular variable RT Virginis during 1985-1996

¹ Instituto Nacional de Astrofísica, Optica y Electrónica, Apartado Postal 51 y 216, Puebla, Pue., Z.P. 72000, México
² Astro-cosmic centre of Lebedev Physical Institute, Russian Academy of Siences, Leninskij prospect 53, 117912, Moscow, Russia
³ Technological University, Kaunas, Lithuania
⁴ Sternberg Astronomical Institute, Universitetsky prospect 13, 119899, Moscow, Russia

Send offprint request to: J.E. Mendoza-Torres

Received: 5 June 1996
Accepted: 5 March 1997

Abstract

We present a catalog of the 22 GHz maser profiles of the semiregular variable RT Vir. The observations were made from 1985 to 1996 at the RT-22 radio telescope of the Radio Astronomical Station at Pushchino, Russia. Results obtained after the analysis of the integrated fluxes, the average spectra, the centroid velocity and the superposition of the spectra are reported. Anticorrelation of the integrated fluxes of two spectral intervals ( and ) was found. The characteristic time variation of the maser emission at each of these groups was about 5-6 years. This phenomenon may be explained by a variation of the outflow of the matter from the star. The outflow is weakly bipolar. We can suppose that in such a model the enhancement of the outflow occured alternately with a period of about 5-6 years. The anticorrelation of the integrated fluxes of two groups of maser features, located symmetrically relative to the star, may be a result of this alternation.