CHEOPS observations confirm nodal precession in the WASP-33 system

A. M. S. Smith; Sz Csizmadia; V. Van Grootel; M. Lendl; C. M. Persson; G. Olofsson; D. Ehrenreich; M. N. Günther; A. Heitzmann; S. C. C. Barros; A. Bonfanti; A. Brandeker; J. Cabrera; O. D. S. Demangeon; L. Fossati; J. -V. Harre; M. J. Hooton; S. Hoyer; Sz Kalman; S. Salmon; S. G. Sousa; Gy M. Szabó; T. G. Wilson; Y. Alibert; R. Alonso; J. Asquier; T. Bárczy; D. Barrado; W. Baumjohann; W. Benz; N. Billot; L. Borsato; C. Broeg; A. Collier Cameron; A. C. M. Correia; P. E. Cubillos; M. B. Davies; M. Deleuil; A. Deline; B. -O. Demory; A. Derekas; B. Edwards; J. A. Egger; A. Erikson; A. Fortier; M. Fridlund; D. Gandolfi; K. Gazeas; M. Gillon; M. Güdel; J. Hasiba; Ch Helling; K. G. Isaak; L. L. Kiss; J. Korth; K. W. F. Lam; J. Laskar; A. Lecavelier des Etangs; D. Magrin; P. F. L. Maxted; B. Merín; C. Mordasini; V. Nascimbeni; R. Ottensamer; I. Pagano; E. Pallé; G. Peter; D. Piazza; G. Piotto; D. Pollacco; D. Queloz; R. Ragazzoni; N. Rando; H. Rauer; I. Ribas; N. C. Santos; G. Scandariato; D. Ségransan; A. E. Simon; M. Stalport; S. Sulis; S. Udry; S. Ulmer-Moll; J. Venturini; E. Villaver; V. Viotto; I. Walter; N. A. Walton; S. Wolf

doi:10.1051/0004-6361/202452151

CHEOPS observations confirm nodal precession in the WASP-33 system

A. M. S. Smith^*, Sz Csizmadia, V. Van Grootel, M. Lendl, C. M. Persson, G. Olofsson, D. Ehrenreich, M. N. Günther, A. Heitzmann, S. C. C. Barros, A. Bonfanti, A. Brandeker, J. Cabrera, O. D. S. Demangeon, L. Fossati, J. -V. Harre, M. J. Hooton, S. Hoyer, Sz Kalman, S. SalmonS. G. Sousa, Gy M. Szabó, T. G. Wilson, Y. Alibert, R. Alonso, J. Asquier, T. Bárczy, D. Barrado, W. Baumjohann, W. Benz, N. Billot, L. Borsato, C. Broeg, A. Collier Cameron, A. C. M. Correia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, B. -O. Demory, A. Derekas, B. Edwards, J. A. Egger, A. Erikson, A. Fortier, M. Fridlund, D. Gandolfi, K. Gazeas, M. Gillon, M. Güdel, J. Hasiba, Ch Helling, K. G. Isaak, L. L. Kiss, J. Korth, K. W. F. Lam, J. Laskar, A. Lecavelier des Etangs, D. Magrin, P. F. L. Maxted, B. Merín, C. Mordasini, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, M. Stalport, S. Sulis, S. Udry, S. Ulmer-Moll, J. Venturini, E. Villaver, V. Viotto, I. Walter, N. A. Walton, S. Wolf

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

Aims. We aim to observe the transits and occultations of WASP-33 b, 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.

Methods. 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.

Results. We measure an orbital obliquity 111.3_−0.7^+0.2 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.

Original language	English
Article number	A128
Number of pages	18
Journal	Astronomy & Astrophysics
Volume	693
Early online date	13 Jan 2025
DOIs	https://doi.org/10.1051/0004-6361/202452151
Publication status	Published - Jan 2025

Keywords

Planets and satellites: dynamical evolution and stability
Planets and satellites: fundamental parameters
Planets and satellites: gaseous planets
Planets and satellites: individual: WASP-33b
Stars: oscillations
Stars: individual: WASP-33

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Smith-2024-CHEOPS-observations-confirm-A&A-693-A128-CCBY
Copyright © The Authors 2024. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Final published version, 7.19 MBLicence: CC BY

PLATO 22-25: Support for the PLATO Development Phase 2022-2025: Planet candidate ranking and validation
Cameron, A. C. (PI)
Science & Technology Facilities Council
1/04/22 → 31/03/25
Project: Standard
AO2 - Professor Andrew Cameron: Project AO2 - Andrew Cameron
Cameron, A. C. (PI)
Science & Technology Facilities Council
1/04/21 → 31/03/24
Project: Standard
H2020 MSCA ITN EJD 2019: H2020 MSCA ITN EJD 2019 CHAMELEON
Helling, C. (PI)
European Commission
1/06/20 → 31/05/24
Project: Standard

CHEOPS observations confirm nodal precession in the WASP-33 system (dataset)
Cameron, A. C. (Creator), VizieR On-line Data Catalog, 2025
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/693/A128
Dataset

Cite this

Smith, A. M. S., Csizmadia, S., Van Grootel, V., Lendl, M., Persson, C. M., Olofsson, G., Ehrenreich, D., Günther, M. N., Heitzmann, A., Barros, S. C. C., Bonfanti, A., Brandeker, A., Cabrera, J., Demangeon, O. D. S., Fossati, L., Harre, J. .-V., Hooton, M. J., Hoyer, S., Kalman, S., ... Wolf, S. (2025). CHEOPS observations confirm nodal precession in the WASP-33 system. Astronomy & Astrophysics, 693, Article A128. https://doi.org/10.1051/0004-6361/202452151

@article{887d16589f174b8ebf220b6b84fa4e5b,

title = "CHEOPS observations confirm nodal precession in the WASP-33 system",

abstract = "Aims. We aim to observe the transits and occultations of WASP-33 b, 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.Methods. 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.Results. We measure an orbital obliquity 111.3−0.7+0.2 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.",

keywords = "Planets and satellites: dynamical evolution and stability, Planets and satellites: fundamental parameters, Planets and satellites: gaseous planets, Planets and satellites: individual: WASP-33b, Stars: oscillations, Stars: individual: WASP-33",

author = "Smith, {A. M. S.} and Sz Csizmadia and {Van Grootel}, V. and M. Lendl and Persson, {C. M.} and G. Olofsson and D. Ehrenreich and G{\"u}nther, {M. N.} and A. Heitzmann and Barros, {S. C. C.} and A. Bonfanti and A. Brandeker and J. Cabrera and Demangeon, {O. D. S.} and L. Fossati and Harre, {J. -V.} and Hooton, {M. J.} and S. Hoyer and Sz Kalman and S. Salmon and Sousa, {S. G.} and Szab{\'o}, {Gy M.} and Wilson, {T. G.} and Y. Alibert and R. Alonso and J. Asquier and T. B{\'a}rczy and D. Barrado and W. Baumjohann and W. Benz and N. Billot and L. Borsato and C. Broeg and Cameron, {A. Collier} and Correia, {A. C. M.} and Cubillos, {P. E.} and Davies, {M. B.} and M. Deleuil and A. Deline and Demory, {B. -O.} and A. Derekas and B. Edwards and Egger, {J. A.} and A. Erikson and A. Fortier and M. Fridlund and D. Gandolfi and K. Gazeas and M. Gillon and M. G{\"u}del and J. Hasiba and Ch Helling and Isaak, {K. G.} and Kiss, {L. L.} and J. Korth and Lam, {K. W. F.} and J. Laskar and {Lecavelier des Etangs}, A. and D. Magrin and Maxted, {P. F. L.} and B. Mer{\'i}n and C. Mordasini and V. Nascimbeni and R. Ottensamer and I. Pagano and E. Pall{\'e} and G. Peter and D. Piazza and G. Piotto and D. Pollacco and D. Queloz and R. Ragazzoni and N. Rando and H. Rauer and I. Ribas and Santos, {N. C.} and G. Scandariato and D. S{\'e}gransan and Simon, {A. E.} and M. Stalport and S. Sulis and S. Udry and S. Ulmer-Moll and J. Venturini and E. Villaver and V. Viotto and I. Walter and Walton, {N. A.} and S. Wolf",

note = "Funding: ACC acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. TWi acknowledges support from the UKSA and the University of Warwick. CHe acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). PM acknowledges support from STFC research grant number ST/R000638/1. NCSa acknowledges funding by the European Union (ERC, FIERCE, 101052347). NAW acknowledges UKSA grant ST/R004838/1.",

year = "2025",

month = jan,

doi = "10.1051/0004-6361/202452151",

language = "English",

volume = "693",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Smith, AMS, Csizmadia, S, Van Grootel, V, Lendl, M, Persson, CM, Olofsson, G, Ehrenreich, D, Günther, MN, Heitzmann, A, Barros, SCC, Bonfanti, A, Brandeker, A, Cabrera, J, Demangeon, ODS, Fossati, L, Harre, J-V, Hooton, MJ, Hoyer, S, Kalman, S, Salmon, S, Sousa, SG, Szabó, GM, Wilson, TG, Alibert, Y, Alonso, R, Asquier, J, Bárczy, T, Barrado, D, Baumjohann, W, Benz, W, Billot, N, Borsato, L, Broeg, C, Cameron, AC, Correia, ACM, Cubillos, PE, Davies, MB, Deleuil, M, Deline, A, Demory, B-O, Derekas, A, Edwards, B, Egger, JA, Erikson, A, Fortier, A, Fridlund, M, Gandolfi, D, Gazeas, K, Gillon, M, Güdel, M, Hasiba, J, Helling, C, Isaak, KG, Kiss, LL, Korth, J, Lam, KWF, Laskar, J, Lecavelier des Etangs, A, Magrin, D, Maxted, PFL, Merín, B, Mordasini, C, Nascimbeni, V, Ottensamer, R, Pagano, I, Pallé, E, Peter, G, Piazza, D, Piotto, G, Pollacco, D, Queloz, D, Ragazzoni, R, Rando, N, Rauer, H, Ribas, I, Santos, NC, Scandariato, G, Ségransan, D, Simon, AE, Stalport, M, Sulis, S, Udry, S, Ulmer-Moll, S, Venturini, J, Villaver, E, Viotto, V, Walter, I, Walton, NA & Wolf, S 2025, 'CHEOPS observations confirm nodal precession in the WASP-33 system', Astronomy & Astrophysics, vol. 693, A128. https://doi.org/10.1051/0004-6361/202452151

TY - JOUR

T1 - CHEOPS observations confirm nodal precession in the WASP-33 system

AU - Smith, A. M. S.

AU - Csizmadia, Sz

AU - Van Grootel, V.

AU - Lendl, M.

AU - Persson, C. M.

AU - Olofsson, G.

AU - Ehrenreich, D.

AU - Günther, M. N.

AU - Heitzmann, A.

AU - Barros, S. C. C.

AU - Bonfanti, A.

AU - Brandeker, A.

AU - Cabrera, J.

AU - Demangeon, O. D. S.

AU - Fossati, L.

AU - Harre, J. -V.

AU - Hooton, M. J.

AU - Hoyer, S.

AU - Kalman, Sz

AU - Salmon, S.

AU - Sousa, S. G.

AU - Szabó, Gy M.

AU - Wilson, T. G.

AU - Alibert, Y.

AU - Alonso, R.

AU - Asquier, J.

AU - Bárczy, T.

AU - Barrado, D.

AU - Baumjohann, W.

AU - Benz, W.

AU - Billot, N.

AU - Borsato, L.

AU - Broeg, C.

AU - Cameron, A. Collier

AU - Correia, A. C. M.

AU - Cubillos, P. E.

AU - Davies, M. B.

AU - Deleuil, M.

AU - Deline, A.

AU - Demory, B. -O.

AU - Derekas, A.

AU - Edwards, B.

AU - Egger, J. A.

AU - Erikson, A.

AU - Fortier, A.

AU - Fridlund, M.

AU - Gandolfi, D.

AU - Gazeas, K.

AU - Gillon, M.

AU - Güdel, M.

AU - Hasiba, J.

AU - Helling, Ch

AU - Isaak, K. G.

AU - Kiss, L. L.

AU - Korth, J.

AU - Lam, K. W. F.

AU - Laskar, J.

AU - Lecavelier des Etangs, A.

AU - Magrin, D.

AU - Maxted, P. F. L.

AU - Merín, B.

AU - Mordasini, C.

AU - Nascimbeni, V.

AU - Ottensamer, R.

AU - Pagano, I.

AU - Pallé, E.

AU - Peter, G.

AU - Piazza, D.

AU - Piotto, G.

AU - Pollacco, D.

AU - Queloz, D.

AU - Ragazzoni, R.

AU - Rando, N.

AU - Rauer, H.

AU - Ribas, I.

AU - Santos, N. C.

AU - Scandariato, G.

AU - Ségransan, D.

AU - Simon, A. E.

AU - Stalport, M.

AU - Sulis, S.

AU - Udry, S.

AU - Ulmer-Moll, S.

AU - Venturini, J.

AU - Villaver, E.

AU - Viotto, V.

AU - Walter, I.

AU - Walton, N. A.

AU - Wolf, S.

N1 - Funding: ACC acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. TWi acknowledges support from the UKSA and the University of Warwick. CHe acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). PM acknowledges support from STFC research grant number ST/R000638/1. NCSa acknowledges funding by the European Union (ERC, FIERCE, 101052347). NAW acknowledges UKSA grant ST/R004838/1.

PY - 2025/1

Y1 - 2025/1

N2 - Aims. We aim to observe the transits and occultations of WASP-33 b, 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.Methods. 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.Results. We measure an orbital obliquity 111.3−0.7+0.2 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.

AB - Aims. We aim to observe the transits and occultations of WASP-33 b, 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.Methods. 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.Results. We measure an orbital obliquity 111.3−0.7+0.2 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.

KW - Planets and satellites: dynamical evolution and stability

KW - Planets and satellites: fundamental parameters

KW - Planets and satellites: gaseous planets

KW - Planets and satellites: individual: WASP-33b

KW - Stars: oscillations

KW - Stars: individual: WASP-33

U2 - 10.1051/0004-6361/202452151

DO - 10.1051/0004-6361/202452151

M3 - Article

SN - 0004-6361

VL - 693

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A128

ER -

CHEOPS observations confirm nodal precession in the WASP-33 system

Abstract

Keywords

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Projects

PLATO 22-25: Support for the PLATO Development Phase 2022-2025: Planet candidate ranking and validation

AO2 - Professor Andrew Cameron: Project AO2 - Andrew Cameron

H2020 MSCA ITN EJD 2019: H2020 MSCA ITN EJD 2019 CHAMELEON

Datasets

CHEOPS observations confirm nodal precession in the WASP-33 system (dataset)

Cite this