LITHIUM-RICH CLASSICAL CEPHEID V1033 CYG: EVOLUTIONARY STATUS

Abstract

We investigate evolutional status ofcepheid V1033 Cyg in this work, its period of lightvariation consists 4 d .94 and the star is a real candidateon first crossing of instability stripe (IS) (as well asα of UMi). At first crossing of instability stripe, thatlasts all close 1000 years, cepheids demonstrate therapid increase of period, sometimes is a presence ofstrong line of lithium 6707 ˚ A. Such objects knows onlyfour in our Galaxy, one of them - V1033 Cyg. Duringincluded in a instability stripe amplitude of pulsationsheadily grows from a zero to some permanent size, andon leaving from (IS) - again falls to a zero. For verifica-tion this phenomenon in the Astronomical observatoryof Odesa National University (Ukraine) on the 48-cmtelescope AZT-3, equipped by CCD photometer withthe optical sensor Sony ICX429ALL, a 1864 measuringof light V1033 Cyg were done in the filter of V and713 in the filter R, that are partly presented in theTable. 1 and Fig. 2, and fully accessible to addresshttp://cdsarc.ustrasbg.fr/viz-bin/cat. Considerablechange of amplitude it is not got by us. The positionof cepheid is certain by us in the (IS) - it appeared thatstar is near her center. In this phase evolutional todevelopment and it must not be observed considerablechange of amplitude (color index). The light curves,effective temperature and luminosity of V1033 Cygare consistent with fundamental mode pulsation for aclassical Cepheid on the center of the instability strip.