On oxygen-rich SR variables in the solar neighborhood

Authors : Tuncay ÖZDEMİR

Pages : 13-26

View : 17 | Download : 11

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Brightness distribution of variable stars was investigated based on good Hipparcos parallaxes of semiregular variables insert ignore into journalissuearticles values(SRVs); in the solar neighborhood, and it is shown that the order of the variability types Lb, SR, SRb, SRa, and Mira is, statistically, an order of increasing brightness along the red giant branch and asymptotic giant branch. In addition, it is also shown that the majority of Miras are above and majority of SRVs are below the tip of the red giant branch. The periods of SRVs that fall in Wood`s sequence C insert ignore into journalissuearticles values(fundamental mode); of large Magellanic clouds were identified. Statistically, the order of SR, SRb, and Mira variables with increasing period and increasing absolute magnitude is the same in six infrared insert ignore into journalissuearticles values(IR); band wavelengths. The slope of the P-L relation for SR $+$ SRb variables in sequence C increases systematically with wavelength in the near IR. This indicates that circumstellar IR emission increases with increasing period from the shorter period SRVs to Miras, which is consistent with the high mass loss rate found in long period Miras. insert ignore into journalissuearticles values(J-K);-M$_{K}$ diagram suggests that the sequence Lb, SR, SRb, SRab insert ignore into journalissuearticles values(emission);, and Mira may be an evolutionary sequence.
Keywords : Stars, distances, fundamental parameters, late type stars, oscillations