EFFECTIVE TEMPERATURE AND RADIAL VELOCITY OF THE SMALL AMPLITUDE CEPHEID POLARIS (alpha UMi) IN 2015

I. A. Usenko, V. V. Kovtyukh, A. S. Miroshnichenko, S. Danford

Анотація


We present the results of an analysis of 21 spectra of alpha UMi (Polaris) obtained in September – December 2015. Frequency analysis shows an increase of the pulsation period up to 8.6 min in comparison to the 2007 observational set. The radial velocity amplitude comes to 4.16 kms-1, and it approximately twice the one found in 2007. The average Teff = 6017 K, and it is close to the value determined for the 2001–2004 set. Therefore Polaris moves to the red edge of the Cepheid instability strip (CIS).


Ключові слова


Stars; radial velocities; Cepheids; overtone pulsations; alpha Umi

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Посилання


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DOI: http://dx.doi.org/10.18524/1810-4215.2016.29.85061

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