The SuperWASP catalogue of 4963 RR Lyr stars: identification of 983 Blazhko effect candidates

Abstract

Aims. We set out to compile a catalogue of RRab pulsating variables in the SuperWASP archive and identify candidate Blazhko effect objects within this catalogue. We analysed their light curves and power spectra for correlations in their common characteristics to further our understanding of the phenomenon. Methods. Pulsation periods were found for each SWASP RRab object using phase dispersion minimisation techniques. Low frequency periodic signals detected in the CLEAN power spectra of RRab stars were matched with modulation sidebands and combined with pairs of sidebands to produce a list of candidate Blazhko periods. A novel technique was used in an attempt to identify Blazhko effect stars by comparing scatter at different parts of the folded light curve. Pulsation amplitudes were calculated based on phase folded light curves. Results. The SuperWASP RRab catalogue consists of 4963 objects of which 3397 are previously unknown. We discovered 983 distinct candidates for Blazhko effect objects, 613 of these being previously unknown in the literature as RR Lyrae stars, and 894 are previously unknown to be Blazhko effect stars. Correlations were investigated between the scatter of points on the light curve, the periods and amplitudes of the objects' pulsations, and those of the Blazhko effect. Conclusions. A statistical analysis has been performed on a large population of Blazhko effect stars from the wide-field SuperWASP survey. No correlations were found between the Blazhko period and other parameters including the Blazhko amplitude, although we confirmed a lower rate of occurrence of the Blazhko effect in long pulsation period objects.

Are all RR Lyrae stars modulated?

“…Therefore, we zoomed to the upper envelopes in the middle and lower panels. 3 The 0.1 c/d upper limit for the modulation frequency f m is supported by the small number of BL stars with f m > 0.1 c/d -see Greer et al (2017) and the lack of such stars in the dataset analyzed in this paper. 4 It is recalled that this is the size of the largest side lobe.…”

Suppressed phase variations in a high amplitude rapidly oscillating Ap star pulsating in a distorted quadrupole mode

“…We derive a temperature of 7600 ± 200 K, and show the fit in Fig 2. The cores of the hydrogen Balmer lines are not fitted well by the model. This is a known problem with LTE models which under-predict the depth of strong lines that are formed high in the atmosphere and subject to non-LTE effects (Gray 2008;Smalley 2014). Coupled with this, the so-called core-wing anomaly is observed in Ap stars (Cowley et al 2001;Kochukhov et al 2002).…”

“…It also produces excellent data for the study of stellar variability. For full details of the SuperWASP project, see Pollacco et al (2006); for examples of stellar variability studies that have been conducted with the data, we refer the reader to the following papers: Maxted et al (2008); Thomas et al (2010); Norton et al (2011Norton et al ( , 2016; Smalley et al (2011Smalley et al ( , 2014Smalley et al ( , 2017; Holdsworth et al (2014aHoldsworth et al ( , 2017; Bowman et al (2015); Greer et al (2017).…”

The spectral Petersen diagram as a new tool to map pulsation modes in variable stars

“…The VVV Survey focused on RRab stars (and identified 960) as these are easier to classify, but excluded RRc stars from their search (Minniti et al 2017;Contreras Ramos et al 2018). The same is true for the SuperWASP catalogue of RR Lyr stars (Greer et al 2017), and the MA-CHO survey (Alcock et al 2000;Greer et al 2017). The PanSTARRS classification work is still in progress (Juhász & Molnár 2018).…”