Publication
Title
Historical vanishing of the Blazhko effect of RR Lyr from the GEOS and Kepler surveys
Author
Abstract
RR Lyr is one of the most studied variable stars. Its light curve has been regularly monitored since the discovery of its periodic variability in 1899. The analysis of all observed maxima allows us to identify two primary pulsation states, defined as pulsation over a long (P-0 longer than 0.56684 d) and a short (P-0 shorter than 0.56682 d) primary pulsation period. These states alternate with intervals of 13-16 yr, and are well defined after 1943. The 40.8-d periodical modulations of the amplitude and the period (i.e. the Blazhko effect) were noticed in 1916. We provide homogeneous determinations of the Blazhko period in the different primary pulsation states. The Blazhko period does not follow the variations of P-0 and suddenly diminished from 40.8 d to around 39.0 d in 1975. The monitoring of these periodicities deserved, and still deserves, a continuous and intensive observational effort. For this purpose, we have built dedicated, transportable and autonomous small instruments, Very Tiny Telescopes (VTTs), to observe the times of maximum brightness of RR Lyr. As immediate results, the VTTs recorded the last change of the P-0 state in mid-2009 and extended the time coverage of the Kepler observations, thus recording a maximum O - C amplitude of the Blazhko effect at the end of 2008, followed by the historically smallest O - C amplitude in late 2013. This decrease is still ongoing and the VTTs are ready to monitor the expected increase in the next few years.
Language
English
Source (journal)
Monthly notices of the Royal Astronomical Society. - Oxford, 1983, currens
Publication
Oxford : 2014
ISSN
0035-8711 [print]
1365-2966 [online]
Volume/pages
441 :2 (2014) , p. 1435-1443
ISI
000336494800039
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 26.04.2018
Last edited 15.10.2021