J/A+A/693/A128 WASP-33 CHEOPS light curves (Smith+, 2025)
CHEOPS observations confirm nodal precession in the WASP-33 system.
Smith A.M.S., Csizmadia Sz., Van Grootel V., Lendl M., Persson C.M.,
Olofsson G., Ehrenreich D., Gunther M.N., Heitzmann A., Barros S.C.,
Bonfanti A., Brandeker A., Cabrera J., Demangeon O.D.S., Fossati L.,
Harre J.-V., Hooton M.J., Hoyer S., Kalman Sz., Salmon S., Sousa S.G.,
Szabo M.Gy., Wilson T.G., Alibert Y., Alonso R., Asquier J., Barczy T.,
Barrado D., Baumjohann W., Benz W., Billot N., Borsato L., Broeg C.,
Collier Cameron A., Correia A.C.M., Cubillos P.E., Davies M.B., Deleuil M.,
Deline A., Demory B.-O., Derekas A., Edwards B., Egger J.A., Erikson A.,
Fortier A., Fridlund M., Gandolfi D., Gazeas K., Gillon M., Gudel M.,
Hasiba J., Helling C., Isaak K.G., Kiss L., Korth J., Lam K.W.F.,
Laskar J., Lecavelier des Etangs A., Magrin D., Maxted P.F.L., Merin B.,
Mordasini C., Nascimbeni V., Ottensamer R., Pagano I., Palle E., Peter G.,
Piazza D., Piotto G., Pollacco D., Queloz D., Ragazzoni R., Rando N.,
Rauer H., Ribas I., Santos N.C., Scandariato G., Segransan D., Simon A.E.,
Stalport M., Sulis S., Udry S., Ulmer-Moll S., Venturini J., Villaver E.,
Viotto V., Walter I., Walton N.A., Wolf S.
<Astron. Astrophys. 693, A128 (2025)>
=2025A&A...693A.128S 2025A&A...693A.128S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Photometry ; Optical
Keywords: planets and satellites: dynamical evolution and stability -
planets and satellites: fundamental parameters -
planets and satellites: gaseous planets -
planets and satellites: individual:: WASP-33 b -
stars: oscillations - stars: individual: WASP-33
Abstract:
We aim to observe the transits and occultations of WASP-33b, which
orbits a rapidly-rotating δ Scuti pulsator, with the goal of
measuring the orbital obliquity via the gravity-darkening effect, and
constraining the geometric albedo via the occultation depth.
We observed four transits and four occultations with CHEOPS, and
employ a variety of techniques to remove the effects of the stellar
pulsations from the light curves, as well as the usual CHEOPS
systematic effects. We also performed a comprehensive analysis of
low-resolution spectral and Gaia data to re-determine the stellar
properties of WASP-33.
We measure an orbital obliquity 111.3+0.2-0.7 degrees, which is
consistent with previous measurements made via Doppler tomography. We
also measure the planetary impact parameter, and confirm that this
parameter is undergoing rapid secular evolution as a result of nodal
precession of the planetary orbit. This precession allows us to
determine the second-order fluid Love number of the star, which we
find agrees well with the predictions of theoretical stellar models.
We are unable to robustly measure a unique value of the occultation
depth, and emphasise the need for long-baseline observations to better
measure the pulsation periods.
Description:
Raw CHEOPS photometry from both the PIPE and DRP reductions for both
the transit and occultations of WASP-33b. The detrended transit
photometry is also presented.
Objects:
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RA (2000) DE Designation(s)
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02 26 51.05 +37 33 01.7 WASP-33 = HD 15082
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
w33_drp.dat 58 3542 Raw CHEOPS photometry from DRP reduction
w33_pipe.dat 43 3499 Raw CHEOPS photometry from PIPE reduction
detrend.dat 39 2069 Detrended DRP transit photometry
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See also:
J/A+A/526/L10 : Transits of WASP-33 (Herrero+, 2011)
Byte-by-byte Description of file: w33_drp.dat
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Bytes Format Units Label Explanations
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1- 15 F15.10 d Time Barycentric Julian Date (TDB) (BJD-2450000.0)
17- 28 F12.10 --- Flux Relative flux
30- 41 F12.10 --- e_Flux Uncertainty on the flux
43- 56 F14.10 deg Roll Spacecraft roll angle
58 I1 --- Visit Visit no. (see Table 3)
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Byte-by-byte Description of file: w33_pipe.dat
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Bytes Format Units Label Explanations
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1- 15 F15.10 d Time Barycentric Julian Date (TDB) (BJD-2450000.0)
17- 28 F12.10 --- Flux Relative flux
30- 41 F12.10 --- e_Flux Uncertainty on the flux
43 I1 --- Visit Visit no. (see Table 3)
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Byte-by-byte Description of file: detrend.dat
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Bytes Format Units Label Explanations
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1- 15 F15.10 d Time Barycentric Julian Date (TDB) (BJD-2450000.0)
17- 24 F8.6 --- Flux Relative flux
26- 37 F12.10 --- e_Flux Uncertainty on the flux
39 I1 --- Visit Visit no. (see Table 3)
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Acknowledgements:
Alexis M.S. Smith, alexis.smith(at)dlr.de
(End) Alexis M.S. Smith [DLR, Germany], Patricia Vannier [CDS] 06-Dec-2024