Digging Deeper for RR Lyrae Stars with Low Modulation Amplitudes
arXiv:2505.10411 · doi:10.1051/0004-6361/202555264
Abstract
With the goal of searching for very low modulation amplitudes among fundamental mode RR Lyrae stars and assess their incidence rate, we performed a survey of 36 stars observed by the Kepler satellite during the entire four-year period of its mission. The search was conducted by a task-oriented code, designed to find low-amplitude signals in the presence of high-amplitude components and instrumental systematics. We found 7 new modulated stars and negate one earlier claimed star, whereby increasing the number of known Blazhko stars from 17 to 24 and yielding an observed occurrence rate of 67% for the Kepler field. Six of the new stars have the lowest modulation amplitudes found so far, with ~250 ppm Fourier side-lobe amplitudes near the fundamental mode frequency. Because of the small sample size in the Kepler field, we extended the survey to 12 campaign fields observed by K2, the ``two-wheeled'' mission of Kepler. From the 1061 stars we found 514 Blazhko stars. After correcting for the short duration of the time spent on each field, and for the noise dependence of the detections, we arrived at an underlying occurrence rate of ~75% - likely a lower limit for the true rate of Blazhko stars in the K2 fields.
Submitted to Astronomy and Astrophysics; after the first (positive) referee report; 11 pages with 10 figures; lightweight, with 1.7 Mb; nice, old-format references linked to paper abstracts
References in corpus (25)
- The K2 Mission: Characterization and Early results
- Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
- A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
- Correcting systematic effects in a large set of photometric lightcurves
- HAT-P-11b: A Super-Neptune Planet Transiting a Bright K Star in the Kepler Field
- A Trend Filtering Algorithm for wide field variability surveys
- EVEREST: Pixel Level Decorrelation of K2 Light curves
- An update to the EVEREST K2 pipeline: Short cadence, saturated stars, and Kepler-like photometry down to Kp = 15
- The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?
- The MACHO Project Large Magellanic Cloud variable star inventory. XI. Frequency analysis of the fundamental mode RR Lyrae stars
- Two Transiting Earth-size Planets Near Resonance Orbiting a Nearby Cool Star
- Fourier analysis of non-Blazhko ab-type RR Lyrae stars observed with the Kepler space telescope
- Fourier decomposition and frequency analysis of the pulsating stars with P < 1day in the OGLE database. II. Multiperiodic RR Lyrae variables in the Galactic Bulge
- Long time-scale behavior of the Blazhko effect from rectified Kepler data
- First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
- Blazhko effect in the Galactic bulge fundamental mode RR~Lyrae stars I: Incidence rate and differences between modulated and non-modulated stars
- Blazhko effect in the Galactic bulge fundamental mode RR Lyrae stars II: Modulation shapes, amplitudes and periods
- Extended Aperture Photometry of K2 RR Lyrae stars
- Are all RR Lyrae stars modulated?
- Revisiting the Kepler non-Blazhko RR Lyrae sample: Cycle-to-cyle variations and additional modes
- The Blazhko effect and additional excited modes in RR Lyrae stars
- The SuperWASP catalogue of 4963 RR Lyr stars: identification of 983 Blazhko effect candidates
- Automated Extended Aperture Photometry of K2 variable stars
- The SERMON project: 48 new field Blazhko stars and an investigation of modulation-period distribution
- Blazhko type fundamental-mode RR Lyrae stars in the globular cluster, M3