First observations of W Virginis stars with K2: detection of period doubling

Abstract

We present the first analysis of W Vir stars observed by the Kepler space telescope in the K2 mission. Clear cycle-to-cycle variation were detected in the light curves of KT Sco and the globular cluster member M80-V1. While the variations in the former star seems to be irregular on the short time scale of the K2 data, the latter appears to experience period doubling in its pulsation. Ground-based colour data confirmed that both stars are W Vir-type pulsators, while a comparison with historical photometric time-series data revealed drastic period changes in both stars. For comparison we reexamine ground-based observations of W Vir, the prototype of the class, and conclude that it shows period doubling instead of mode beating. These results support the notion that nonlinear dynamics plays an important role in the pulsation of W Virginis-type stars.

8 pages, 7 figures, accepted for publication in MNRAS

References in corpus (22)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Dartmouth Stellar Evolution Database
• The K2 Mission: Characterization and Early results
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• Northern Sky Variability Survey (NSVS): Public data release
• The ACS Survey of Galactic Globular Clusters. VII. Relative Ages
• The Catalina Surveys Periodic Variable Star Catalog
• The first WASP public data release
• HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands
• Homogeneous age dating of 55 Galactic globular clusters. Clues to the Galaxy formation mechanisms
• FITSH -- a software package for image processing
• Does Kepler unveil the mystery of the Blazhko effect? First detection of period doubling in Kepler Blazhko RR Lyrae stars
• The first INTEGRAL-OMC catalogue of optically variable sources
• The period-luminosity relation for type II Cepheids in globular clusters
• Discovery of period doubling in BL Herculis stars of the OGLE survey. Observations and theoretical models
• Survey of non-linear hydrodynamic models of type-II Cepheids
• Pushing the limits, episode 2: K2 observations of extragalactic RR Lyrae stars in the dwarf galaxy Leo IV
• CoRoT space photometry of seven Cepheids
• Multicolor photometry of the Type II Cepheid prototype W Virginis
• Light Curves and Period Changes of Type II Cepheids in the Globular Clusters M3 and M5
• Intriguing triple-mode RR Lyrae star with period doubling
• On the interchange of alternating-amplitude pulsation cycles

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