Photometric Behavior of Five Long-Period Pulsating Stars

TL;DR

This study analyzes a century of observational data to examine cyclic brightness and amplitude variations in five long-period Mira-type stars, revealing quasi-periodic behavior and period changes over time.

Contribution

It provides a long-term analysis of brightness and amplitude variations in five Mira stars using nearly 100 years of observational data, highlighting cyclic patterns and period changes.

Findings

All stars show cyclic variations in brightness and amplitude.

Quasi-periods of brightness variation are approximately 1400, 1025, and 1680 days for T Cep, U UMi, and U Cyg.

Brightness variation periods change over time, but mean values are used for analysis.

Abstract

The variation of average brightness during the time and the variation of the amplitude of the Mira-type stars T Cep, X CrB, U UMi, U Cyg, BG Cyg is studied. For the research, the observations of the members of the French association of observers of variable stars (AFOEV) covering almost 100 years are used. All stars show cyclic variations of the specified parameters. For T Cep, U UMi and U Cyg, the values of quasi-period of the variations of average brightness are about 1400, 1025 and 1680 days, respectively. For the stars T Cep, U UMi and BG Cyg, the period of the brightness variations changes, but we used a mean one. The dependences {\guillemotleft}average brightness - JD{\guillemotright} and {\guillemotleft}amplitude - JD{\guillemotright} are plotted. Results are discussed.