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Up: Evolution of maser

4. Conclusions

Long-term regular observations for more than 10 years of 22 GHz tex2html_wrap_inline1154 maser emission of the semiregular variable RT Vir have been carried out. The main results are as follows:

1. A catalogue of 68 tex2html_wrap_inline1380O spectra of RT Vir is compiled.

2. The division of the tex2html_wrap_inline1154 spectrum of RT Vir into three parts is argued and is related to the morphology of the source of the maser emission.

3. The integrated fluxes of the two parts of the spectrum (tex2html_wrap_inline1384 and tex2html_wrap_inline1160) vary with the same timescale of about 5-6 years.

4. Anticorrelation of the integrated fluxes of these parts of the spectrum, which may be due to alternating increasing of the intensity of the bipolar outflow, is observed.

5. The period of the tex2html_wrap_inline1154 maser activity in the RT Vir direction is much longer than the average period of star variation.

Acknowledgements

We would like to thank the associates of the Radio Astronomical Station of the Lebedev Physical Institute for their help during the observations at the Pushchino RT-22 radio telescope and the Russian Foundation for Fundamental Research (Project Code 95-02-05087-a) for financial support.



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