Architecture of TOI-561 planetary system

G. Piotto, T. Zingales*, L. Borsato, J. A. Egger, A. C.M. Correia, A. E. Simon, H. G. Florén, S. G. Sousa, P. F.L. Maxted, D. Nardiello, L. Malavolta, T. G. Wilson, Y. Alibert, V. Adibekyan, A. Bonfanti, R. Luque, N. C. Santos, M. J. Hooton, L. Fossati, A. M.S. SmithS. Salmon, G. Lacedelli, R. Alonso, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, N. Billot, A. Brandeker, C. Broeg, M. Buder, A. Collier Cameron, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D.S. Demangeon, B. O. Demory, A. Derekas, B. Edwards, D. Ehrenreich, A. Erikson, A. Fortier, M. Fridlund, D. Gandolfi, K. Gazeas, M. Gillon, M. Güdel, M. N. Günther, A. Heitzmann, Ch Helling, K. G. Isaak, L. L. Kiss, J. Korth, K. W.F. Lam, J. Laskar, A. Lecavelier Des Etangs, M. Lendl, P. Leonardi, D. Magrin, G. Mantovan, C. Mordasini, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, R. Ottensamer, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, D. Sicilia, M. Stalport, S. Sulis, Gy M. Szabó, S. Udry, S. Ulmer-Moll, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, J. N. Winn, S. Wolf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present new observations from CHEOPS (CHaracterising ExOPlanet Satellite) and TESS (Transiting Exoplanet Survey Satellite) to clarify the architecture of the planetary system hosted by the old Galactic thick disc star TOI-561. Our global analysis, which also includes previously published photometric and radial velocity data, incontrovertibly proves that TOI-561 is hosting at least four transiting planets with periods of 0.44 d (TOI-561 b), 10.8 d (TOI-561 c), 25.7 d (TOI-561 d), and 77.1 d (TOI-561 e) and a fifth non-transiting candidate, TOI-561f with a period of 433 d. The precise characterization of TOI-561's orbital architecture is interesting since old and metal-poor thick disc stars are less likely to host ultrashort-period super-Earths like TOI-561 b. The new period of planet -e is consistent with the value obtained using radial velocity alone and is now known to be 77.14399 ± 0.00025 d, thanks to the new CHEOPS and TESS transits. The new data allowed us to improve its radius (Rp = 2.517 ± 0.045 R from 5 per cent to 2 per cent precision) and mass(Mp = 12.4 ± 1.4 M?) estimates, implying a density of ρp = 0.778 ± 0.097 ρ. Thanks to recent TESS observations and the focused CHEOPS visit of the transit of TOI-561 e, a good candidate for exomoon searches, the planet's period is finally constrained, allowing us to predict transit times through 2030 with 20-min accuracy. We present an updated version of the internal structure of the four transiting planets. We finally performed a detailed stability analysis, which confirmed the long-term stability of the outer planet TOI-561 f.

Original languageEnglish
Pages (from-to)2763-2774
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume535
Issue number3
DOIs
Publication statusPublished - 1 Dec 2024

Keywords

  • ephemerides
  • planets and satellites: dynamical evolution and stability
  • planets and satellites: fundamental parameters
  • planets and satellites: interiors
  • techniques: photometric
  • techniques: radial velocities

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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