Long-term photometric variations in the candidate white-dwarf pulsar AR Scorpii from K2 , CRTS, and ASAS-SN observations

Littlefield, Colin; Garnavich, Peter M.; Kennedy, Mark R.; Callanan, Paul J.; Shappee, Benjamin; Holoien, Thomas

Long-term photometric variations in the candidate white-dwarf pulsar AR Scorpii from K2 , CRTS, and ASAS-SN observations

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Published version

Date

2017-08-10

Authors

Littlefield, Colin

Garnavich, Peter M.

Kennedy, Mark R.

Callanan, Paul J.

Shappee, Benjamin

Holoien, Thomas

Publisher

Institute of Physics Publishing

Published Version

10.3847/2041-8213/aa8300

Abstract

We analyze long-cadence Kepler K2 observations of AR Sco from 2014, along with survey photometry obtained between 2005 and 2016 by the Catalina Real-Time Sky Survey and the All-Sky Automated Survey for Supernovae. The K2 data show the orbital modulation to have been fairly stable during the 78 days of observations, but we detect aperiodic deviations from the average waveform with an amplitude of ~2% on a timescale of a few days. A comparison of the K2 data with the survey photometry reveals that the orbital waveform gradually changed between 2005 and 2010, with the orbital maximum shifting to earlier phases. We compare these photometric variations with proposed models of this unusual system.

Keywords

Binaries: close , Pulsars , Stars: individual (AR Sco) , Stars: magnetic field , White dwarfs

Citation

Colin, L., Peter, G., Mark, K., Paul, C., Benjamin, S. and Thomas, H. (2017) 'Long-term Photometric Variations in the Candidate White-dwarf Pulsar AR Scorpii from K2 , CRTS, and ASAS-SN Observations', The Astrophysical Journal Letters, 845(1), pp. L7. doi: 10.3847/2041-8213/aa8300