J/MNRAS/440/1470 Ji light curves of WTS-2 (Birkby+, 2014)
WTS-2 b: a hot Jupiter orbiting near its tidal destruction radius around
a K dwarf.
Birkby J.L., Cappetta M., Cruz P., Koppenhoefer J., Ivanyuk O.,
Mustill A.J., Hodgkin S.T., Pinfield D.J., Sipocz B., Kovacs G., Saglia R.,
Pavlenko Y., Barrado D., Bayo A., Campbell D., Catalan S., Fossati L.,
Galvez-Ortiz M.-C., Kenworthy M., Lillo-Box J., Martin E.L., Mislis D.,
de Mooij E.J.W., Nefs S.V., Snellen I.A.G., Stoev H., Zendejas J.,
del Burgo C., Barnes J., Goulding N., Haswell C.A., Kuznetsov M.,
Lodieu N., Murgas F., Palle E., Solano E., Steele P., Tata R.
<Mon. Not. R. Astron. Soc., 440, 1470-1489 (2014)>
=2014MNRAS.440.1470B 2014MNRAS.440.1470B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry, infrared
Keywords: surveys - planets and satellites: detection -
planets and satellites: dynamical evolution and stability -
planets and satellites: fundamental parameters -
planets and satellites: individual: WTS-2 b
Abstract:
We report the discovery of WTS-2 b, an unusually close-in 1.02-d hot
Jupiter (MP=1.12MJ, RP=1.30RJ) orbiting a K2V star, which has
a possible gravitationally bound M-dwarf companion at 0.6-arcsec
separation contributing ∼20% of the total flux in the observed J-band
light curve. The planet is only 1.5 times the separation from its host
star at which it would be destroyed by Roche lobe overflow, and has a
predicted remaining lifetime of just ∼40Myr, assuming a tidal
dissipation quality factor of Q'*=106. Q'* is a key factor in
determining how frictional processes within a host star affect the
orbital evolution of its companion giant planets, but it is currently
poorly constrained by observations. We calculate that the orbital
decay of WTS-2 b would correspond to a shift in its transit arrival
time of Tshift∼17s after 15yr assuming Q'*=106. A shift less
than this would place a direct observational constraint on the lower
limit of Q'* in this system. We also report a correction to the
previously published expected Tshift for WASP-18 b, finding that
Tshift=356s after 10yr for Q'*106, which is much larger than the
estimated 28s quoted in WASP-18 b discovery paper. We attempted to
constrain Q'* via a study of the entire population of known
transiting hot Jupiters, but our results were inconclusive, requiring
a more detailed treatment of transit survey sensitivities at long
periods. We conclude that the most informative and straightforward
constraints on Q'* will be obtained by direct observational
measurements of the shift in transit arrival times in individual hot
Jupiter systems. We show that this is achievable across the mass
spectrum of exoplanet host stars within a decade, and will directly
probe the effects of stellar interior structure on tidal dissipation.
Description:
The infrared light curves of the WTS were generated from time series
photometry taken with the WFCAM imager mounted at the prime focus of
UKIRT.
In order to confirm the transit of WTS-2 b and to help constrain the
transit model, on 2010 July 18 we obtained further time series
photometry in the Sloan i band using the Wide Field Camera (WFC) on
the 2.5m Isaac Newton Telescope (INT) at Roque de Los Muchachos, La
Palma.
Objects:
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RA (2000) DE Designation(s)
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19 34 55.87 +36 48 55.8 WTS-2 b = WTS-2b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 33 1138 The observed WFCAM J-band light-curve data for
WTS-2 b without correction for dilution
table3.dat 33 67 The observed INT i-band light curve for WTS-2 b
without correction for dilution
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Byte-by-byte Description of file: table1.dat table3.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d HJD Heliocentric Julian date
17- 23 F7.4 mag mag Magnitude in Band
26- 31 F6.4 mag e_mag rms uncertainty on mag (1)
33 A1 --- Band [Ji] Observed band (2)
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Note (1): For J band, the errors are estimated using a standard noise model,
including contributions from Poisson noise within the object aperture,
sky noise, readout noise, and errors in the sky background estimation.
For i-band, the errors were derived in the same manner as for the J band but
have been scaled so that the out-of-transit baseline has a reduced χ2=1
when compared to a flat line to avoid underestimating the errors (see Fig. 3).
Note (2): Observed band as follows:
J = WFCAM J-band. Magnitude in WFCAM system
i = INT Sloan i-band.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Jul-2015