KIC 4552982: OUTBURSTS AND ASTEROSEISMOLOGY FROM THE LONGEST PSEUDO-CONTINUOUS LIGHT CURVE OF A ZZ Ceti

ABSTRACT We present the Kepler light curve of KIC 4552982, the first ZZ Ceti (hydrogen-atmosphere pulsating white dwarf star) discovered in the Kepler field of view. Our data span more than 1.5 years, with a 86% duty cycle, making it the longest pseudo-continuous light curve ever recorded for a ZZ C...

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Bibliographic Details
Published in:The Astrophysical journal 2015-08, Vol.809 (1), p.1-12
Main Authors: Bell, Keaton J., Hermes, J. J., Bischoff-Kim, A., Moorhead, Sean, Montgomery, M. H., Østensen, Roy, Castanheira, Barbara G., Winget, D. E.
Format: Article
Language:English
Subjects:
AMPLITUDES
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COMPARATIVE EVALUATIONS
DETECTION
Flux
Frequency variation
HYDROGEN
Light curve
MASS
OSCILLATIONS
Outbursts
Pulsation
PULSATIONS
ROTATION
SATELLITE ATMOSPHERES
Signatures
Stars
stars: activity
stars: individual (KIC 4552982, WD J191643.83+393849.7)
stars: oscillations
VISIBLE RADIATION
WHITE DWARF STARS
white dwarfs
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Summary:ABSTRACT We present the Kepler light curve of KIC 4552982, the first ZZ Ceti (hydrogen-atmosphere pulsating white dwarf star) discovered in the Kepler field of view. Our data span more than 1.5 years, with a 86% duty cycle, making it the longest pseudo-continuous light curve ever recorded for a ZZ Ceti. This extensive data set provides the most complete coverage to date of amplitude and frequency variations in a cool ZZ Ceti. We detect 20 independent frequencies of variability in the data that we compare with asteroseismic models to demonstrate that this star has a mass . We identify a rotationally split pulsation mode and derive a probable rotation period for this star of 17.47 0.04 hr. In addition to pulsation signatures, the Kepler light curve exhibits sporadic, energetic outbursts that increase the star's relative flux by 2%-17%, last 4-25 hr, and recur on an average timescale of 2.7 days. These are the first detections of a new dynamic white dwarf phenomenon that may be related to the pulsations of this relatively cool ( K) ZZ Ceti star near the red edge of the instability strip.
ISSN:0004-637X
1538-4357
1538-4357
DOI:10.1088/0004-637X/809/1/14