DOI: https://doi.org/10.18524/1810-4215.2008.21.86879

STELLAR INVESTIGATION IN THE OPEN CLUSTER OF POLARIS

I. A. Usenko, A. S. Miroshnichenko, V. G. Klochkova, V. E. Panchuk

Анотація


We present the results of our analysis of high-resolution spectroscopic observations of Cepheid α UMi (Polaris A), and main-sequence type stars Polaris B, and HD 5914, an optical companion and a member of Polaris open cluster. The last ones are objects with high projected rotational velocities v sin i = 110 km s-1 and 100 km -1, respectively. The derived atmosphere parameters are: Polaris A: Teff=6020 K; log g=2.2; Vt=4.2 km s-1; Polaris B: Teff=6900 K; log g=4.3; Vt=2.5 km s-1; HD 5914: Teff=8800 K; log g=4.0; Vt=2.0 km s-1. C, Na and Mg content in last two stars is close to solar, whereas for Polaris A these values are typical for Cepheid after the first dredge-up stage. The distances to Polaris B and HD 5914 are 109.5 and 108 pc, respectively. The RV pulsational amplitude of Polaris A increased to 7.5 km s-1 in 2003, decreased to 0.6 km s-1 in 2005 and increased anew to 2.5 s-1 in 2007.

Ключові слова


Stars; abundances - Stars; distances - Stars; Cepheids - Stars; main-sequence stars - Stars; individual - α UMi (Polaris A); Polaris B; HD 5914

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Посилання


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