Automated Extended Aperture Photometry of K2 variable stars

Abstract

Proper photometric data are challenging to obtain in the K2 mission of the Kepler space telescope due to strong systematics caused by the two-wheel-mode operation. It is especially true for variable stars wherein physical phenomena occur on timescales similar to the instrumental signals. We originally developed a method with the aim to extend the photometric aperture to be able to compensate the motion of the telescope which we named Extended Aperture Photometry (EAP). Here we present the outline of the automatized version of the EAP method, an open-source pipeline called autoEAP. We compare the light curve products to other photometric solutions for examples chosen from high-amplitude variable stars. Besides the photometry, we developed a new detrending method, which is based on phase dispersion minimization and is able to eliminate long-term instrumental signals for periodic variable stars.

15 pages, 12 figures. Accepted for publication in PASP. Code available on GitHub: https://github.com/konkolyseismolab/autoeap. Light curve data available: https://konkoly.hu/KIK/data_en.html

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Cited by in corpus (9)

• Gaia DR3: Specific processing and validation of all-sky RR Lyrae and Cepheid stars -- The Cepheid sample
• Frequency analysis of the first-overtone RR Lyrae stars based on the Extended Aperture Photometry from the K2 data
• Time series analysis of bright TESS RRc stars: Additional modes, phase variations and more
• To Grow Old and Peculiar: A Survey of Anomalous Variable Stars in M80 and Age Determination using K2 and Gaia
• Type II and anomalous Cepheids in the Kepler K2 mission
• Connections between the cycle-to-cycle light curve and O-C variations of the non-Blazhko RR Lyrae stars
• Digging Deeper for RR Lyrae Stars with Low Modulation Amplitudes
• Exploring Low-Amplitude Variability in First Overtone Cepheids with TESS
• Matching seismic masses for RR Lyrae-type and oscillating red horizontal-branch stars in M4