Period changes in omega Centauri RR Lyrae stars

Abstract

A century of observations of omega Centauri allows us to accurately follow the period changes of a large sample of variable stars. Although the period changes are composed of monotone and irregular changes, period increases dominate in most of the RRab stars. The typical period increase rates are of the same order of magnitude as model calculations predict for the evolved, redward phase of horizontal branch evolution. For the 44 well observed RRab stars which show monotonic period changes, a mean rate of 0.15 d/Myr has been found. The period changes of the first overtone RRc type stars show a much more complex, irregular behavior.

23 pages (LaTeX text and tables); 25 figures(.gif), to appear in AJ

References in corpus (1)

• The Globular Cluster Omega Centauri and the Oosterhoff Dichotomy

Cited by in corpus (31)

• Long-term Properties of Accretion Disks in X-ray Binaries: I. the variable third period in SMC X-1
• Kepler photometry of RRc stars: peculiar double-mode pulsations and period doubling
• Stellar evolution through the ages: period variations in galactic RRab stars as derived from the GEOS database and TAROT telescopes
• On the RR Lyrae stars in globulars: IV. $\omega$ Centauri Optical UBVRI Photometry
• CCD time-series photometry of the globular cluster NGC 6981: Variable star census and physical parameter estimates
• Cluster AgeS Experiment. Catalog of Variable Stars in the Globular Cluster Omega Centauri
• On the RR Lyrae stars in globulars: V. the complete Near-Infrared (JHKs) census of omega Centauri RR Lyrae variables
• Long-term photometric monitoring of RR Lyr stars in M3
• Cyclic variations in O-C diagrams of field RR Lyrae stars as a result of LiTE
• Variable stars in the globular cluster NGC 7492. New discoveries and physical parameters determination
• Long-term photometric monitoring of Messier 5 variables: I. Period changes of RR Lyrae stars
• On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of $\omega$ Cen
• An Updated Census of RR~Lyrae Stars in the Globular Cluster $\omega$~Centauri (NGC\,5139)
• The unusually large population of Blazhko variables in the globular cluster NGC 5024 (M53)
• Early-type variables in the Magellanic Clouds. I. Beta Cephei stars in the LMC bar
• Studies of RR Lyrae Variables in Binary Systems. I.: Evidence of a Trimodal Companion Mass Distribution
• Period Change Similarities among the RR Lyrae Variables in Oosterhoff I and Oosterhoff II Globular Systems
• The Blazhko behaviour of RR Geminorum II -- long-term photometric results
• A first-overtone RR Lyrae star with cyclic period changes
• Milky Way archaeology using RR Lyrae and type II Cepheids I. The Orphan stream in 7D using RR Lyrae stars
• Characteristics of bright ab-type RR Lyrae stars from the ASAS and WASP surveys
• Revisiting the Kepler non-Blazhko RR Lyrae sample: Cycle-to-cyle variations and additional modes
• A cautionary tale of interpreting O-C diagrams: period instability in a classical RR Lyr Star Z CVn mimicking as a distant companion
• Frequency analysis of the first-overtone RR Lyrae stars based on the Extended Aperture Photometry from the K2 data
• A New Overview of Secular Period Changes of RR Lyrae stars inM5
• Time series analysis of bright TESS RRc stars: Additional modes, phase variations and more
• Humps and bumps: The effects of shocks on the optical light curves of fundamental-mode RR Lyrae stars
• Near-ultraviolet detections of four dwarf nova candidates in the globular cluster 47 Tucanae
• A search for period changes of eight short-period Type II Cepheids
• Period changes in the RR Lyrae stars of NGC 6171 (M107)
• PIPS, an advanced platform for period detection in time series -- I. Fourier-likelihood periodogram and application to RR Lyrae Stars