J/A+A/535/A7 Transit light curves of WASP-10 b (Maciejewski+, 2011)
Analysis of new high-precision transit light curves of WASP-10 b:
starspot occultations, small planetary radius, and high metallicity.
Maciejewski G., Raetz S., Nettelmann N., Seeliger M., Adam C., Nowak G.,
Neuhaeuser R.
<Astron. Astrophys. 535, A7 (2011)>
=2011A&A...535A...7M 2011A&A...535A...7M
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry, CCD
Keywords: stars: starspots - stars: individual: WASP-10 -
planets and satellites: individual: WASP-10 b
Abstract:
The WASP-10 planetary system is intriguing because different values of
radius have been reported for its transiting exoplanet. The host star
exhibits activity in terms of photometric variability, which is caused
by the rotational modulation of the spots. Moreover, a periodic
modulation has been discovered in transit timing of WASP-10 b, which
could be a sign of an additional body perturbing the orbital motion of
the transiting planet. We attempt to refine the physical parameters of
the system, in particular the planetary radius, which is crucial for
studying the internal structure of the transiting planet. We also
determine new mid-transit times to confirm or refute observed
anomalies in transit timing. We acquired high-precision light curves
for four transits of WASP-10 b in 2010. Assuming various
limb-darkening laws, we generated best-fit models and redetermined
parameters of the system. The prayer-bead method and Monte Carlo
simulations were used to derive error estimates. Three transit light
curves exhibit signatures of the occultations of dark spots by the
planet during its passage across the stellar disk. The influence of
stellar activity on transit depth is taken into account while
determining system parameters. The radius of WASP-10 b is found to be
no greater than 1.03+0.07-0.03 Jupiter radii, a value
significantly smaller than most previous studies indicate. We
calculate interior structure models of the planet, assuming a
two-layer structure with one homogeneous envelope atop a rock core.
The high value of the WASP-10 b's mean density allows one to consider
the planet's internal structure including 270 to 450 Earth masses of
heavy elements. Our new mid-transit times confirm that transit timing
cannot be explained by a constant period if all literature data points
are considered. They are consistent with the ephemeris assuming a
periodic variation of transit timing. We show that possible starspot
features affecting the transit's ingress or egress cannot reproduce
variations in transit timing at the observed amplitude.
Description:
Light curves of four WASP-10 b's transits observed in 2010 are given.
Data were collected with the Calar Alto Faint Object Spectrograph
(CAFOS) on the 2.2-m telescope at Calar Alto Observatory (Spain).
Magnitudes in R band were determined with the aperture photometry
method against a comparison star.
Objects:
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RA (2000) DE Designation(s)
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23 15 58.3 +31 27 46 WASP-10 = 2MASS J23155829+3127462
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
w10aug03.dat 36 174 The light curve observed on 3 Aug, 2010
w10aug06.dat 36 213 The light curve observed on 6 Aug, 2010
w10sep06.dat 36 164 The light curve observed on 6 Sep, 2010
w10sep09.dat 36 184 The light curve observed on 9 Sep, 2010
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Byte-by-byte Description of file: w10*.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d JD Julian Day, based on Coordinated Universal Time
17- 25 F9.6 mag Rmag Relative magnitude in R band
29- 36 F8.6 mag e_Rmag Magnitude error
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Acknowledgements:
Gracjan Maciejewski, gm(at)astri.uni.torun.pl
(End) Gracjan Maciejewski [TCfA, Poland], Patricia Vannier [CDS] 22-Sep-2011