PULSATIONAL ACTIVITY OF THE SMALL–AMPLITUDE CEPHEID POLARIS (α UMi) IN 2016-2017
Journal Title: Odessa Astronomical Publications - Year 2017, Vol 30, Issue
Abstract
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.
Authors and Affiliations
I. A. Usenko, V. Kovtyukh, A. S. Miroshnichenko, S. Danford
ON THE E/P-COSMIC RAYS AS MEDIATORS OF VISCOUS FORCES THAT CREATE SHOCK AND VORTEX STRUCTURES IN THE RADIO GALAXIES
There are for the galaxies of FRII type (like Cygnus A) studied a number of hydrodynamic and kinetic processes to transport of magnetized plasma with cosmic rays, and a stratification process of RG-lobe because of e\p-co...
VARIABILITY FEATURES OF THE RADIO SOURCE OT 081 IN CENTIMETER WAVELENGTH RANGE
OT 081 – BL Lac object, intensively studied for many years in a wide range of the electromagnetic spectrum. We used observational data for 1999-2011 years, obtained on radio telescope at Michigan State University (UMRA...
PERIOD VARIATIONS AND POSSIBLE THIRD COMPONENTS IN THE ECLIPSING BINARIES AH TAURI AND ZZ CASSIOPEIAE
In our research, we investigated two variable stars: AH Tau and ZZ Cas. They are eclipsing binary stars of W Ursae IMajories and Lyrae types. The period between eclipses of these stars changes with time. The reason for...
THE RESULTS OF OBSERVATIONS OF MUTUAL PHENOMENA OF THE GALILEAN SATELLITES OF JUPITER IN 2009 AND 2015 IN NIKOLAEV ASTRONOMICAL OBSERVATORY
The Earth and Jupiter once in 6 years have simultaneous passage of the ecliptic plane due to their orbital movement around the Sun. This makes it possible to observe the mutual occultations and eclipses in the Galilean s...
RE-CLASSIFICATION OF THE NEGLECTED VARIABLE V480 AQL
We present the results of multicoloured photometric study of previously neglected variable star V480 Aql. Our V RI observations prove that this star belongs to classical Cepheids with the period of P = 19d.0016. We also...