Architecture of TOI-561 planetary system

Journal Article · 20 November 2024 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stae2440 · OSTI ID:2478571

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

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 $$77.14399\pm 0.00025$$ d, thanks to the new CHEOPS and TESS transits. The new data allowed us to improve its radius ($$R_p = 2.517 \pm 0.045\,\mathrm{ R}_{\rm{\oplus }}$$ from 5 per cent to 2 per cent precision) and mass ($$M_p = 12.4 \pm 1.4\, \mathrm{ M}_{\rm{\oplus }}$$) estimates, implying a density of $$\rho _p = 0.778 \pm 0.097\, \rho _{\rm{\oplus }}$$. 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.

• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain
• OSTI ID: 2478571
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 3 Vol. 535; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English