J/A+A/659/A74 CHEOPS phase curve of WASP-189 b (Deline+, 2022)
The atmosphere and architecture of WASP-189 b probed by its CHEOPS phase curve.
Deline A., Hooton M.J., Lendl M., Morris B., Salmon S., Olofsson G.,
Broeg C., Ehrenreich D., Beck M., Brandeker A., Hoyer S., Sulis S.,
Van Grootel V., Bourrier V., Demangeon O., Demory B.-O., Heng K.,
Parviainen H., Serrano L.M., Singh V., Bonfanti A., Fossati L., Kitzmann D.,
Sousa S.G., Wilson T.G., Alibert Y., Alonso R., Anglada G., Barczy T.,
Barrado Navascues D., Barros S.C.C., Baumjohann W., Beck T., Bekkelien A.,
Benz W., Billot N., Bonfils X., Cabrera J., Charnoz S., Collier Cameron A.,
Corral van Damme C., Csizmadia Sz., Davies M.B., Deleuil M., Delrez L.,
de Roche T., Erikson A., Fortier A., Fridlund M., Futyan D., Gandolfi D.,
Gillon M., Guedel M., Gutermann P., Hasiba J., Isaak K.G., Kiss L.,
Laskar J., Lecavelier des Etangs A., Lovis C., Magrin D., Maxted P.F.L.,
Munari M., Nascimbeni V., Ottensamer R., Pagano I., Palle E., Peter G.,
Piotto G., Pollacco D., Queloz D., Ragazzoni R., Rando N., Rauer H.,
Ribas I., Santos N.C., Scandariato G., Segransan D., Simon A.E.,
Smith A.M.S., Steller M., Szabo Gy.M., Thomas N., Udry S., Walter I.,
Walton N.
<Astron. Astrophys. 659, A74 (2022)>
=2022A&A...659A..74D 2022A&A...659A..74D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, A-type ; Exoplanets ;
Photometry
Keywords: techniques: photometric - planets and satellites: atmospheres -
planets and satellites: individual: WASP-189 b
Abstract:
Gas giants orbiting close to hot and massive early-type stars can
reach dayside temperatures that are comparable to those of the coldest
stars. These "ultra-hot Jupiters" have atmospheres made of ions and
atomic species from molecular dissociation and feature strong
day-to-night temperature gradients. Photometric observations at
different orbital phases provide insights on the planet atmospheric
properties.
We analyse the photometric observations of WASP-189 acquired with the
instrument CHEOPS to derive constraints on the system architecture and
the planetary atmosphere.
We implement a light curve model suited for asymmetric transit shape
caused by the gravity-darkened photosphere of the fast-rotating host
star. We also model the reflective and thermal components of the
planetary flux, the effect of stellar oblateness and light-travel time
on transit-eclipse timings, the stellar activity and CHEOPS
systematics.
From the asymmetric transit, we measure the size of the ultra-hot
Jupiter WASP-189, Rp=1.600-0.016+0.017RJ, with a precision of
1%, and the true orbital obliquity of the planetary system
Ψp=89.6±1.2deg (polar orbit). We detect no significant hotspot
offset from the phase curve and obtain an eclipse depth
δecl=96.5-5.0+4.5ppm, from which we derive an upper limit
on the geometric albedo: Ag<0.48. We also find that the eclipse
depth can only be explained by thermal emission alone in the case of
extremely inefficient energy redistribution. Finally, we attribute the
photometric variability to the stellar rotation, either through
superficial inhomogeneities or resonance couplings between the
convective core and the radiative envelope.
Based on the derived system architecture, we predict the eclipse depth
in the upcoming TESS observations to be up to ∼165ppm.
High-precision detection of the eclipse in both CHEOPS and TESS
passbands might help disentangle between reflective and thermal
contributions. We also expect the right ascension of the ascending
node of the orbit to precess due to the perturbations induced by the
stellar quadrupole moment J2 (oblateness).
Description:
Raw, normalised and residual photometric light curves of the WASP-189
planetary system obtained with the space-based instrument CHEOPS.
Planet-related signal only (transit, occultation and planetary flux)
is also reported after correction of the instrumental systematic noise
and the stellar activity.
Objects:
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RA (2000) DE Designation(s)
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15 02 44.87 -03 01 52.99 WASP-189 = HD 133112
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ap_phot.dat 185 12228 *DEFAULT aperture photometry
psf_phot.dat 185 12215 *PSF photometry
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Note on psf_phot.dat: Extracted with the PIPE code
(https://github.com/alphapsa/PIPE).
Note on ap_phot.dat : Extracted by the data reduction pipeline (Hoyer et al.,
2020A&A...635A..24H 2020A&A...635A..24H) using a circular aperture with a 25-pixel radius.
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See also:
J/A+A/643/A94 : CHEOPS WASP-189 b transit light curve (Lendl+, 2020)
Byte-by-byte Description of file: ap_phot.dat psf_phot.dat
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Bytes Format Units Label Explanations
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1- 18 F18.10 d BJD Barycentric Julian date (TDB)
20- 37 F18.8 e- rawFlux Raw flux (in electrons)
39- 56 F18.12 e- e_rawFlux Raw flux error (in electrons)
58- 75 F18.16 --- NFlux ? Normalised flux
77- 97 E21.15 --- e_NFlux ? Normalised flux error
99-122 E24.16 --- Res ? Normalised residuals
124-144 E21.15 --- e_Res ? Normalised residual error
146-163 F18.16 --- detrendedLC ? Planet-related signal
165-185 E21.15 --- e_detrendedLC ? Planet-related signal error
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Acknowledgements:
Adrien Deline, adrien.deline(at)unige.ch
(End) Patricia Vannier [CDS] 15-Jan-2022