J/A+A/626/A38 Kepler-17 long-term photometry (Lanza+, 2019)
Stellar activity and rotation of the planet host Kepler-17 from long-term
space-borne photometry.
Lanza A.F., Netto Y., Bonomo A.S., Parviainen H., Valio A., Aigrain S.
<Astron. Astrophys. 626, A38 (2019)>
=2019A&A...626A..38L 2019A&A...626A..38L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry
Keywords: stars: activity - stars: rotation - stars: late-type - starspots -
planetary systems - techniques: photometry
Abstract:
The study of young Sun-like stars is of fundamental importance to
understand the magnetic activity and rotational evolution of the Sun.
Space-borne photometry by the Kepler telescope provides unprecedented
datasets to investigate these phenomena in Sun-like stars. We present
a new analysis of the entire Kepler photometric time series of the
moderately young Sun-like star Kepler-17 that is accompanied by a
transiting hot Jupiter. We applied a maximum-entropy spot model to the
long-cadence out-of-transit photometry of the target to derive maps of
the starspot filling factor versus the longitude and the time. These
maps are compared to the spots occulted during transits to validate
our reconstruction and derive information on the latitudes of the
starspots. We find two main active longitudes on the photosphere of
Kepler-17, one of which has a lifetime of at least ∼1400 days,
although with a varying level of activity. The latitudinal
differential rotation is of solar type, that is, with the equator
rotating faster than the poles. We estimate a minimum relative
amplitude {DELTA}{OMEGA}/{OMEGA} between ∼0.08±0.05 and 0.14±0.05,
our determination being affected by the finite lifetime of individual
starspots and depending on the adopted spot model parameters. We find
marginal evidence of a short-term intermittent activity cycle of
∼48-days and an indication of a longer cycle of 400-600 days
characterized by an equatorward migration of the mean latitude of the
spots as in the Sun. The rotation of Kepler-17 is likely to be
significantly affected by the tides raised by its massive close-by
planet. We confirm the reliability of maximum-entropy spot models to
map starspots in young active stars and characterize the activity and
differential rotation of this young Sun-like planetary host.
Description:
Kepler light curves of the planet host Kepler-17 obtained with the
de-trending methods of Bonomo and Lanza or the ARC2 pipeline as
described in Sect. 2 of the above paper. These light curves are
modelled with a maximum-entropy spot model and the results are
discussed in the paper.
Objects:
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RA (2000) DE Designation(s)
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19 53 34.86 +47 48 54.0 Kepler-17 = KOI-203
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
k17bola.dat 63 47376 Kepler-17 light curve obtained by applying the
de-trending as in Bonomo & Lanza
(2012A&A...547A..37B 2012A&A...547A..37B)
k17arc2.dat 65 40653 Kepler-17 ARC2 pipeline ligth curve
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Byte-by-byte Description of file: k17bola.dat
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Bytes Format Units Label Explanations
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11- 21 F11.6 d Time Time in BJD starting at 2454900.0 (BJD-2454900.0)
35- 42 F8.6 --- Flux Normalized flux
56- 63 F8.6 --- e_Flux Standard deviation of flux normalized as flux
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Byte-by-byte Description of file: k17arc2.dat
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Bytes Format Units Label Explanations
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11- 21 F11.6 d Time Time in BJD starting at 2454833.0 (BJD-2454833.0)
34- 43 F10.8 --- Flux Normalized flux
56- 65 F10.8 --- e_Flux ?=- Standard deviation of flux normalized as flux
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Acknowledgements:
Antonio Lanza, antonino.lanza(at)inaf.it
(End) Patricia Vannier [CDS] 30-Apr-2019