PULSATIONAL ACTIVITY OF THE SMALL–AMPLITUDE CEPHEID POLARIS (α UMi) IN 2016-2017

Автор(и)

  • I. A. Usenko Astronomical Observatory, Odessa National University, Mykolaiv Astronomical Observatory, Україна
  • V. V. Kovtyukh Astronomical Observatory, Odessa National University, Україна
  • A. S. Miroshnichenko Dept. of Physics and Astronomy, University of North Carolina at Greensboro, США
  • S. Danford Dept. of Physics and Astronomy, University of North Carolina at Greensboro, США

DOI:

https://doi.org/10.18524/1810-4215.2017.30.114382

Ключові слова:

stars, radial velocities, Cepheids, effective temperatures, Cepheids α UMi

Анотація

We present the results of an analysis of 49 spectra of α UMi (Polaris) obtained during August – December 2016 and January – March 2017. Frequency analysis displays an unexpected decrease of the pulsational period up to 17.3 min in comparison to the 2015 observational set. The radial velocity amplitude was reduced to 3.43 km s−1 in 2016 and to 3.31km s−1 in the beginning of 2017 in comparison with 4.16 km s−1 in 2015. This result is also unexpected, because during the last decade a gradual amplitude growth has been observed. The average Teff = 6021 K determined from the 2016–2017 data is close to the values determined for the 2001–2015 set.

Посилання

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Опубліковано

2017-11-08

Номер

Розділ

Астрофізика (зоряні атмосфери, взаємодіючі подвійні системи, змінні зорі)