| |
 |
| Paper: |
Optical and Radio Monitoring of a Sample of Late-Type Variables |
| Volume: |
203, The Impact of Large-Scale Surveys on Pulsating Star Research, IAU Colloquium 176 |
| Page: |
126 |
| Authors: |
Esipov, V. F.; Lekht, E. E.; Pashchenko, M. I.; Rudnitskij, G. M. |
| Abstract: |
Results of regular observations of about 20 Miras and semiregular variables (o Cet, R Leo, R Aql, U Her, χ Cyg, R Tri, and others) in 1994-1999 are presented. The monitoring includes optical spectroscopy, optical (UBV) and infrared (JHKLM) photometry, high-resolution radio spectroscopy in the 1.35-cm water-vapour maser line (on the 22-m radio telescope in Pushchino). Optical spectroscopy shows that the appearance of strong Balmer emission lines in Miras may be a rare event, and the presumed shock waves are thus weak. The H2O maser flux generally correlates with visual light curves of the stars with some delay Δϕ=0.1-0.4P (P is the variability period). For R Leo, R Cas, and U Aur strong flares in the Hα line, observed in 1997-1998, were followed by corresponding outbursts of the H2O maser emission about 2P later. This sequence of events is probably caused by a shock wave propagating outward in the stellar atmosphere and consecutively initiating the Hα emission and, later, the maser flare at a larger distance from the stellar surface. |
|
|
|
|
|
