Photo-dynamical characterisation of the TOI-178 resonant chain

A. Leleu; J. -B. Delisle; L. Delrez; E. M. Bryant; A. Brandeker; H. P. Osborn; N. Hara; T. G. Wilson; N. Billot; M. Lendl; D. Ehrenreich; H. Chakraborty; M. N. Günther; M. J. Hooton; Y. Alibert; R. Alonso; D. R. Alves; D. R. Anderson; I. Apergis; D. Armstrong; T. Bárczy; D. Barrado Navascues; S. C. C. Barros; M. P. Battley; W. Baumjohann; D. Bayliss; T. Beck; W. Benz; L. Borsato; C. Broeg; M. R. Burleigh; S. L. Casewell; A. Collier Cameron; A. C. M. Correia; Sz Csizmadia; P. E. Cubillos; M. B. Davies; M. Deleuil; A. Deline; O. D. S. Demangeon; B. -O. Demory; A. Derekas; B. Edwards; A. Erikson; A. Fortier; L. Fossati; M. Fridlund; D. Gandolfi; K. Gazeas; E. Gillen; M. Gillon; M. R. Goad; M. Güdel; F. Hawthorn; A. Heitzmann; Ch Helling; K. G. Isaak; J. S. Jenkins; J. M. Jenkins; A. Kendall; L. L. Kiss; J. Korth; K. W. F. Lam; J. Laskar; D. W. Latham; A. Lecavelier des Etangs; D. Magrin; P. F. L. Maxted; J. McCormac; C. Mordasini; M. Moyano; V. Nascimbeni; G. Olofsson; A. Osborn; R. Ottensamer; I. Pagano; E. Pallé; G. Peter; G. Piotto; D. Pollacco; D. Queloz; R. Ragazzoni; N. Rando; H. Rauer; I. Ribas; G. Ricker; S. Saha; N. C. Santos; G. Scandariato; S. Seager; D. Ségransan; A. E. Simon; A. M. S. Smith; S. G. Sousa; M. Stalport; S. Sulis; Gy M. Szabó; S. Udry; V. Van Grootel; R. Vanderspek; J. Venturini; E. Villaver; J. I. Vinés; N. A. Walton; R. G. West; J. Winn; T. Zivave

doi:10.1051/0004-6361/202450212

Photo-dynamical characterisation of the TOI-178 resonant chain

A. Leleu, J. -B. Delisle, L. Delrez, E. M. Bryant, A. Brandeker, H. P. Osborn, N. Hara, T. G. Wilson, N. Billot, M. Lendl, D. Ehrenreich, H. Chakraborty, M. N. Günther, M. J. Hooton, Y. Alibert, R. Alonso, D. R. Alves, D. R. Anderson, I. Apergis, D. ArmstrongT. Bárczy, D. Barrado Navascues, S. C. C. Barros, M. P. Battley, W. Baumjohann, D. Bayliss, T. Beck, W. Benz, L. Borsato, C. Broeg, M. R. Burleigh, S. L. Casewell, A. Collier Cameron, A. C. M. Correia, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D. S. Demangeon, B. -O. Demory, A. Derekas, B. Edwards, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, K. Gazeas, E. Gillen, M. Gillon, M. R. Goad, M. Güdel, F. Hawthorn, A. Heitzmann, Ch Helling, K. G. Isaak, J. S. Jenkins, J. M. Jenkins, A. Kendall, L. L. Kiss, J. Korth, K. W. F. Lam, J. Laskar, D. W. Latham, A. Lecavelier des Etangs, D. Magrin, P. F. L. Maxted, J. McCormac, C. Mordasini, M. Moyano, V. Nascimbeni, G. Olofsson, A. Osborn, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Ricker, S. Saha, N. C. Santos, G. Scandariato, S. Seager, D. Ségransan, A. E. Simon, A. M. S. Smith, S. G. Sousa, M. Stalport, S. Sulis, Gy M. Szabó, S. Udry, V. Van Grootel, R. Vanderspek, J. Venturini, E. Villaver, J. I. Vinés, N. A. Walton, R. G. West, J. Winn, T. Zivave

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

Abstract

Context. The TOI-178 system consists of a nearby, late-K-dwarf with six transiting planets in the super-Earth to mini-Neptune regime, with radii ranging from to 2.9 R⊕ and orbital periods between 1.9 and 20.7 days. All the planets, but the innermost one, form a chain of Laplace resonances. The fine-tuning and fragility of such orbital configurations ensure that no significant scattering or collision event has taken place since the formation and migration of the planets in the protoplanetary disc, thereby providing important anchors for planet formation models.

Aims. We aim to improve the characterisation of the architecture of this key system and, in particular, the masses and radii of its planets. In addition, since this system is one of the few resonant chains that can be characterised by both photometry and radial velocities, we propose to use it as a test bench for the robustness of the planetary mass determination with each technique.

Methods. We performed a global analysis of all the available photometry from CHEOPS, TESS and NGTS, and radial velocity from ESPRESSO, using a photo-dynamical modelling of the light curve. We also tried different sets of priors on the masses and eccentricity, as well as different stellar activity models, to study their effects on the masses estimated by transit-timing variations (TTVs) and radial velocities (RVs).

Results. We demonstrate how stellar activity prevents a robust mass estimation for the three outer planets using radial velocity data alone. We also show that our joint photo-dynamical and radial velocity analysis has resulted in a robust mass determination for planets c to 𝑔, with precision of ~ 12% for the mass of planet c, and better than 10% for planets d to 𝑔. The new precisions on the radii range from 2 to 3%. The understanding of this synergy between photometric and radial velocity measurements will be valuable for the PLATO mission. We also show that TOI-178 is indeed currently locked in the resonant configuration, librating around an equilibrium of the chain.

Original language	English
Article number	A211
Journal	Astronomy & Astrophysics
Volume	688
Early online date	26 Aug 2024
DOIs	https://doi.org/10.1051/0004-6361/202450212
Publication status	Published - Aug 2024

Keywords

Methods: data analysis
Techniques: photometric
Techniques: radial velocities
Planets and satellites: Atmospheres
Planets and satellites: gaseous planets

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REVEAL: REVEALing Signatures of Habitable Worlds Hidden by Stellar Activity
Cameron, A. C. (PI)
UKRI (EU)
1/08/24 → 31/07/30
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

TOI-178 light curves
Leleu, A. (Creator), Delisle, J.-B. (Creator), Delrez, L. (Creator), Bryant, E. M. (Creator), Brandeker, A. (Creator), Osborn, H. P. (Creator), Hara, N. (Creator), Wilson, T. G. (Creator), Billot, N. (Creator), Lendl, M. (Creator), Ehrenreich, D. (Creator), Chakraborty, H. (Creator), Guenther, M. N. (Creator), Hooton, M. J. (Creator), Alibert, Y. (Creator), Alonso, R. (Creator), Alves, D. R. (Creator), Anderson, D. R. (Creator), Apergis, I. (Creator), Armstrong, D. (Creator), Barczy, T. (Creator), Barrado Navascues, D. (Creator), Barros, S. C. (Creator), Battley, M. P. (Creator), Baumjohann, W. (Creator), Bayliss, D. (Creator), Beck, T. (Creator), Benz, W. (Creator), Borsato, L. (Creator), Broeg, C. (Creator), Burleigh, M. R. (Creator), Casewell, S. L. (Creator), Collier Cameron, A. (Creator), Correia, A. C. M. (Creator), Sz, C. (Creator), Cubillos, P. E. (Creator), Davies, M. B. (Creator), Deleuil, M. (Creator), Deline, A. (Creator), Demangeon, O. D. S. (Creator), Demory, B.-O. (Creator), Derekas, A. (Creator), Edwards, B. (Creator), Erikson, A. (Creator), Fortier, A. (Creator), Fossati, L. (Creator), Fridlund, M. (Creator), Gandolfi, D. (Creator), Gazeas, K. (Creator), Gillen, E. (Creator), Gillon, M. (Creator), Goad, M. R. (Creator), Guedel, M. (Creator), Hawthorn, F. (Creator), Heitzmann, A. (Creator), Ch, H. (Creator), Isaak, K. G. (Creator), Jenkins, J. S. (Creator), Jenkins, J. M. (Creator), Kendall, A. (Creator), Kiss, L. (Creator), Korth, J. (Creator), K.W.F., L. (Creator), Laskar, J. (Creator), Latham, D. W. (Creator), Lecavelier Des Etangs, A. (Creator), Magrin, D. (Creator), Maxted, P. F. L. (Creator), McCormac, J. (Creator), Mordasini, C. (Creator), Moyano, M. (Creator), Nascimbeni, V. (Creator), Olofsson, G. (Creator), Osborn, A. (Creator), Ottensamer, R. (Creator), Pagano, I. (Creator), Palle, E. (Creator), Peter, G. (Creator), Piotto, G. (Creator), Pollacco, D. (Creator), Queloz, D. (Creator), Ragazzoni, R. (Creator), Rando, N. (Creator), Rauer, H. (Creator), Ribas, I. (Creator), Ricker, G. (Creator), Saha, S. (Creator), Santos, N. C. (Creator), Scandariato, G. (Creator), Seager, S. (Creator), Segransan, D. (Creator), Simon, A. E. (Creator), Smith, A. M. S. (Creator), Sousa, S. G. (Creator), Stalport, M. (Creator), Sulis, S. (Creator), M.Gy, S. (Creator), Udry, S. (Creator), Ulmer-Moll, S. (Creator), Van Grootel, V. (Creator), Vanderspek, R. (Creator), Venturini, J. (Creator), Villaver, E. (Creator), Vines, J. I. (Creator), Walton, N. A. (Creator), West, R. G. (Creator), Wheatley, P. J. (Creator), Winn, J. (Creator) & Zivave, T. (Creator), Centre de Donnees Strasbourg (CDS), 2024
DOI: 10.26093/cds/vizier.36880211
Dataset

Cite this

Leleu, A., Delisle, J. .-B., Delrez, L., Bryant, E. M., Brandeker, A., Osborn, H. P., Hara, N., Wilson, T. G., Billot, N., Lendl, M., Ehrenreich, D., Chakraborty, H., Günther, M. N., Hooton, M. J., Alibert, Y., Alonso, R., Alves, D. R., Anderson, D. R., Apergis, I., ... Zivave, T. (2024). Photo-dynamical characterisation of the TOI-178 resonant chain. Astronomy & Astrophysics, 688, Article A211. https://doi.org/10.1051/0004-6361/202450212

@article{493679831a6b4c60b3fcf4a315f5c51e,

title = "Photo-dynamical characterisation of the TOI-178 resonant chain",

abstract = "Context. The TOI-178 system consists of a nearby, late-K-dwarf with six transiting planets in the super-Earth to mini-Neptune regime, with radii ranging from to 2.9 R⊕ and orbital periods between 1.9 and 20.7 days. All the planets, but the innermost one, form a chain of Laplace resonances. The fine-tuning and fragility of such orbital configurations ensure that no significant scattering or collision event has taken place since the formation and migration of the planets in the protoplanetary disc, thereby providing important anchors for planet formation models.Aims. We aim to improve the characterisation of the architecture of this key system and, in particular, the masses and radii of its planets. In addition, since this system is one of the few resonant chains that can be characterised by both photometry and radial velocities, we propose to use it as a test bench for the robustness of the planetary mass determination with each technique.Methods. We performed a global analysis of all the available photometry from CHEOPS, TESS and NGTS, and radial velocity from ESPRESSO, using a photo-dynamical modelling of the light curve. We also tried different sets of priors on the masses and eccentricity, as well as different stellar activity models, to study their effects on the masses estimated by transit-timing variations (TTVs) and radial velocities (RVs).Results. We demonstrate how stellar activity prevents a robust mass estimation for the three outer planets using radial velocity data alone. We also show that our joint photo-dynamical and radial velocity analysis has resulted in a robust mass determination for planets c to 𝑔, with precision of ~ 12% for the mass of planet c, and better than 10% for planets d to 𝑔. The new precisions on the radii range from 2 to 3%. The understanding of this synergy between photometric and radial velocity measurements will be valuable for the PLATO mission. We also show that TOI-178 is indeed currently locked in the resonant configuration, librating around an equilibrium of the chain.",

keywords = "Methods: data analysis, Techniques: photometric, Techniques: radial velocities, Planets and satellites: Atmospheres, Planets and satellites: gaseous planets",

author = "A. Leleu and Delisle, {J. -B.} and L. Delrez and Bryant, {E. M.} and A. Brandeker and Osborn, {H. P.} and N. Hara and Wilson, {T. G.} and N. Billot and M. Lendl and D. Ehrenreich and H. Chakraborty and G{\"u}nther, {M. N.} and Hooton, {M. J.} and Y. Alibert and R. Alonso and Alves, {D. R.} and Anderson, {D. R.} and I. Apergis and D. Armstrong and T. B{\'a}rczy and {Barrado Navascues}, D. and Barros, {S. C. C.} and Battley, {M. P.} and W. Baumjohann and D. Bayliss and T. Beck and W. Benz and L. Borsato and C. Broeg and Burleigh, {M. R.} and Casewell, {S. L.} and Cameron, {A. Collier} and Correia, {A. C. M.} and Sz Csizmadia and Cubillos, {P. E.} and Davies, {M. B.} and M. Deleuil and A. Deline and Demangeon, {O. D. S.} and Demory, {B. -O.} and A. Derekas and B. Edwards and A. Erikson and A. Fortier and L. Fossati and M. Fridlund and D. Gandolfi and K. Gazeas and E. Gillen and M. Gillon and Goad, {M. R.} and M. G{\"u}del and F. Hawthorn and A. Heitzmann and Ch Helling and Isaak, {K. G.} and Jenkins, {J. S.} and Jenkins, {J. M.} and A. Kendall and Kiss, {L. L.} and J. Korth and Lam, {K. W. F.} and J. Laskar and Latham, {D. W.} and {Lecavelier des Etangs}, A. and D. Magrin and Maxted, {P. F. L.} and J. McCormac and C. Mordasini and M. Moyano and V. Nascimbeni and G. Olofsson and A. Osborn and R. Ottensamer and I. Pagano and E. Pall{\'e} and G. Peter and G. Piotto and D. Pollacco and D. Queloz and R. Ragazzoni and N. Rando and H. Rauer and I. Ribas and G. Ricker and S. Saha and Santos, {N. C.} and G. Scandariato and S. Seager and D. S{\'e}gransan and Simon, {A. E.} and Smith, {A. M. S.} and Sousa, {S. G.} and M. Stalport and S. Sulis and Szab{\'o}, {Gy M.} and S. Udry and {Van Grootel}, V. and R. Vanderspek and J. Venturini and E. Villaver and Vin{\'e}s, {J. I.} and Walton, {N. A.} and West, {R. G.} and J. Winn and T. Zivave",

note = "Funding: The contributions at the Mullard Space Science Laboratory by E.M.B. have been supported by STFC through the consolidated grant ST/W001136/1. T.Wi. acknowledges support from the UKSA and the University of Warwick. This research was funded in whole or in part by the UKRI, (Grants ST/X001121/1, EP/X027562/1). A.C.C. acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. E.G. gratefully acknowledges support from the UK Science and Technology Facilities Council (STFC. project reference ST/W001047/1). C.He. acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). P.M. acknowledges support from STFC research grant number ST/R000638/1. N.C.Sa. acknowledges funding by the European Union (ERC, FIERCE, 101052347). N.A.W. acknowledges UKSA grant ST/R004838/1. ",

year = "2024",

month = aug,

doi = "10.1051/0004-6361/202450212",

language = "English",

volume = "688",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Leleu, A, Delisle, J-B, Delrez, L, Bryant, EM, Brandeker, A, Osborn, HP, Hara, N, Wilson, TG, Billot, N, Lendl, M, Ehrenreich, D, Chakraborty, H, Günther, MN, Hooton, MJ, Alibert, Y, Alonso, R, Alves, DR, Anderson, DR, Apergis, I, Armstrong, D, Bárczy, T, Barrado Navascues, D, Barros, SCC, Battley, MP, Baumjohann, W, Bayliss, D, Beck, T, Benz, W, Borsato, L, Broeg, C, Burleigh, MR, Casewell, SL, Cameron, AC, Correia, ACM, Csizmadia, S, Cubillos, PE, Davies, MB, Deleuil, M, Deline, A, Demangeon, ODS, Demory, B-O, Derekas, A, Edwards, B, Erikson, A, Fortier, A, Fossati, L, Fridlund, M, Gandolfi, D, Gazeas, K, Gillen, E, Gillon, M, Goad, MR, Güdel, M, Hawthorn, F, Heitzmann, A, Helling, C, Isaak, KG, Jenkins, JS, Jenkins, JM, Kendall, A, Kiss, LL, Korth, J, Lam, KWF, Laskar, J, Latham, DW, Lecavelier des Etangs, A, Magrin, D, Maxted, PFL, McCormac, J, Mordasini, C, Moyano, M, Nascimbeni, V, Olofsson, G, Osborn, A, Ottensamer, R, Pagano, I, Pallé, E, Peter, G, Piotto, G, Pollacco, D, Queloz, D, Ragazzoni, R, Rando, N, Rauer, H, Ribas, I, Ricker, G, Saha, S, Santos, NC, Scandariato, G, Seager, S, Ségransan, D, Simon, AE, Smith, AMS, Sousa, SG, Stalport, M, Sulis, S, Szabó, GM, Udry, S, Van Grootel, V, Vanderspek, R, Venturini, J, Villaver, E, Vinés, JI, Walton, NA, West, RG, Winn, J & Zivave, T 2024, 'Photo-dynamical characterisation of the TOI-178 resonant chain', Astronomy & Astrophysics, vol. 688, A211. https://doi.org/10.1051/0004-6361/202450212

TY - JOUR

T1 - Photo-dynamical characterisation of the TOI-178 resonant chain

AU - Leleu, A.

AU - Delisle, J. -B.

AU - Delrez, L.

AU - Bryant, E. M.

AU - Brandeker, A.

AU - Osborn, H. P.

AU - Hara, N.

AU - Wilson, T. G.

AU - Billot, N.

AU - Lendl, M.

AU - Ehrenreich, D.

AU - Chakraborty, H.

AU - Günther, M. N.

AU - Hooton, M. J.

AU - Alibert, Y.

AU - Alonso, R.

AU - Alves, D. R.

AU - Anderson, D. R.

AU - Apergis, I.

AU - Armstrong, D.

AU - Bárczy, T.

AU - Barrado Navascues, D.

AU - Barros, S. C. C.

AU - Battley, M. P.

AU - Baumjohann, W.

AU - Bayliss, D.

AU - Beck, T.

AU - Benz, W.

AU - Borsato, L.

AU - Broeg, C.

AU - Burleigh, M. R.

AU - Casewell, S. L.

AU - Cameron, A. Collier

AU - Correia, A. C. M.

AU - Csizmadia, Sz

AU - Cubillos, P. E.

AU - Davies, M. B.

AU - Deleuil, M.

AU - Deline, A.

AU - Demangeon, O. D. S.

AU - Demory, B. -O.

AU - Derekas, A.

AU - Edwards, B.

AU - Erikson, A.

AU - Fortier, A.

AU - Fossati, L.

AU - Fridlund, M.

AU - Gandolfi, D.

AU - Gazeas, K.

AU - Gillen, E.

AU - Gillon, M.

AU - Goad, M. R.

AU - Güdel, M.

AU - Hawthorn, F.

AU - Heitzmann, A.

AU - Helling, Ch

AU - Isaak, K. G.

AU - Jenkins, J. S.

AU - Jenkins, J. M.

AU - Kendall, A.

AU - Kiss, L. L.

AU - Korth, J.

AU - Lam, K. W. F.

AU - Laskar, J.

AU - Latham, D. W.

AU - Lecavelier des Etangs, A.

AU - Magrin, D.

AU - Maxted, P. F. L.

AU - McCormac, J.

AU - Mordasini, C.

AU - Moyano, M.

AU - Nascimbeni, V.

AU - Olofsson, G.

AU - Osborn, A.

AU - Ottensamer, R.

AU - Pagano, I.

AU - Pallé, E.

AU - Peter, G.

AU - Piotto, G.

AU - Pollacco, D.

AU - Queloz, D.

AU - Ragazzoni, R.

AU - Rando, N.

AU - Rauer, H.

AU - Ribas, I.

AU - Ricker, G.

AU - Saha, S.

AU - Santos, N. C.

AU - Scandariato, G.

AU - Seager, S.

AU - Ségransan, D.

AU - Simon, A. E.

AU - Smith, A. M. S.

AU - Sousa, S. G.

AU - Stalport, M.

AU - Sulis, S.

AU - Szabó, Gy M.

AU - Udry, S.

AU - Van Grootel, V.

AU - Vanderspek, R.

AU - Venturini, J.

AU - Villaver, E.

AU - Vinés, J. I.

AU - Walton, N. A.

AU - West, R. G.

AU - Winn, J.

AU - Zivave, T.

N1 - Funding: The contributions at the Mullard Space Science Laboratory by E.M.B. have been supported by STFC through the consolidated grant ST/W001136/1. T.Wi. acknowledges support from the UKSA and the University of Warwick. This research was funded in whole or in part by the UKRI, (Grants ST/X001121/1, EP/X027562/1). A.C.C. acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. E.G. gratefully acknowledges support from the UK Science and Technology Facilities Council (STFC. project reference ST/W001047/1). C.He. acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). P.M. acknowledges support from STFC research grant number ST/R000638/1. N.C.Sa. acknowledges funding by the European Union (ERC, FIERCE, 101052347). N.A.W. acknowledges UKSA grant ST/R004838/1.

PY - 2024/8

Y1 - 2024/8

N2 - Context. The TOI-178 system consists of a nearby, late-K-dwarf with six transiting planets in the super-Earth to mini-Neptune regime, with radii ranging from to 2.9 R⊕ and orbital periods between 1.9 and 20.7 days. All the planets, but the innermost one, form a chain of Laplace resonances. The fine-tuning and fragility of such orbital configurations ensure that no significant scattering or collision event has taken place since the formation and migration of the planets in the protoplanetary disc, thereby providing important anchors for planet formation models.Aims. We aim to improve the characterisation of the architecture of this key system and, in particular, the masses and radii of its planets. In addition, since this system is one of the few resonant chains that can be characterised by both photometry and radial velocities, we propose to use it as a test bench for the robustness of the planetary mass determination with each technique.Methods. We performed a global analysis of all the available photometry from CHEOPS, TESS and NGTS, and radial velocity from ESPRESSO, using a photo-dynamical modelling of the light curve. We also tried different sets of priors on the masses and eccentricity, as well as different stellar activity models, to study their effects on the masses estimated by transit-timing variations (TTVs) and radial velocities (RVs).Results. We demonstrate how stellar activity prevents a robust mass estimation for the three outer planets using radial velocity data alone. We also show that our joint photo-dynamical and radial velocity analysis has resulted in a robust mass determination for planets c to 𝑔, with precision of ~ 12% for the mass of planet c, and better than 10% for planets d to 𝑔. The new precisions on the radii range from 2 to 3%. The understanding of this synergy between photometric and radial velocity measurements will be valuable for the PLATO mission. We also show that TOI-178 is indeed currently locked in the resonant configuration, librating around an equilibrium of the chain.

AB - Context. The TOI-178 system consists of a nearby, late-K-dwarf with six transiting planets in the super-Earth to mini-Neptune regime, with radii ranging from to 2.9 R⊕ and orbital periods between 1.9 and 20.7 days. All the planets, but the innermost one, form a chain of Laplace resonances. The fine-tuning and fragility of such orbital configurations ensure that no significant scattering or collision event has taken place since the formation and migration of the planets in the protoplanetary disc, thereby providing important anchors for planet formation models.Aims. We aim to improve the characterisation of the architecture of this key system and, in particular, the masses and radii of its planets. In addition, since this system is one of the few resonant chains that can be characterised by both photometry and radial velocities, we propose to use it as a test bench for the robustness of the planetary mass determination with each technique.Methods. We performed a global analysis of all the available photometry from CHEOPS, TESS and NGTS, and radial velocity from ESPRESSO, using a photo-dynamical modelling of the light curve. We also tried different sets of priors on the masses and eccentricity, as well as different stellar activity models, to study their effects on the masses estimated by transit-timing variations (TTVs) and radial velocities (RVs).Results. We demonstrate how stellar activity prevents a robust mass estimation for the three outer planets using radial velocity data alone. We also show that our joint photo-dynamical and radial velocity analysis has resulted in a robust mass determination for planets c to 𝑔, with precision of ~ 12% for the mass of planet c, and better than 10% for planets d to 𝑔. The new precisions on the radii range from 2 to 3%. The understanding of this synergy between photometric and radial velocity measurements will be valuable for the PLATO mission. We also show that TOI-178 is indeed currently locked in the resonant configuration, librating around an equilibrium of the chain.

KW - Methods: data analysis

KW - Techniques: photometric

KW - Techniques: radial velocities

KW - Planets and satellites: Atmospheres

KW - Planets and satellites: gaseous planets

U2 - 10.1051/0004-6361/202450212

DO - 10.1051/0004-6361/202450212

M3 - Article

SN - 0004-6361

VL - 688

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A211

ER -

Photo-dynamical characterisation of the TOI-178 resonant chain

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Projects

REVEAL: REVEALing Signatures of Habitable Worlds Hidden by Stellar Activity

AO2 - Professor Andrew Cameron: Project AO2 - Andrew Cameron

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

Datasets

TOI-178 light curves

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