Polaris: History of Pulsation Activity since Discovery

1Usenko, IO, 2Kovtyukh, VV, 3Miroshnichenko, AS, 3Danford, S
1Astronomical Observatory of Odessa National University; Mykolaiv Astronomical Observatory Research Institute
2Astronomical Observatory of Odessa National University
3Department of Physics and Astronomy of the University of North Carolina at Greensboro
Nauka innov. 2017, 13(1):109-113
https://doi.org/10.15407/scin13.01.109
Section: Scientific Framework of Innovation Activities
Language: English
Abstract: 
The pulsation activity of small-amplitude Cepheid Alpha UMi (Polaris) during the period of its radial velocity observations has been analyzed. In the 20th century, Polaris was known to demonstrate a decrease in radial velocity amplitude to the minimum, in the 1980s. Thereafter, the amplitude has increased. The observations of September-December 2015 (21 spectra) obtained by 81cm telescope TCO with spectrograph have showed that radial velocity amplitude comes to 4.16 km/s and is approximately twice higher than the estimates made in 2007, with pulsation period adding 8.6 min.
Keywords: Cepheids, pulsation periods, radial velocities, stars, variable amplitude, α Umi