Exoplanetology: Exoplanets & Exomoons

Architecture Of TOI-561 Planetary System

By Keith Cowing
Status Report
astro-ph.EP
October 27, 2024
Filed under , , , , , , , , , , , , , ,
Architecture Of TOI-561 Planetary System
Stability analysis of the TOI-561 planetary system. For fixed initial conditions (Table 2), the parameter space of the system is explored by varying the orbital period and the eccentricity of planet- 𝑓 . The step size is 0.25 day in the orbital period and 0.0025 in the eccentricity. For each initial condition, the system is integrated over 10 000 yr, and a stability indicator is calculated, which involved a frequency analysis of the mean longitude of the inner planet. The chaotic diffusion is measured by the variation in the main frequency. Red points correspond to highly unstable orbits, while blue points correspond to orbits that are likely to be stable on Gyr timescales. The black curve corresponds to 𝐾 = 1.88 m/s and the black dot shows the values of the best fit solution (Table 2). — astro-ph.EP

We present new observations from CHEOPS and TESS to clarify the architecture of the planetary system hosted by the old Galactic thick disk 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 days (TOI-561 b), 10.8 days (TOI-561 c), 25.7 days (TOI-561 d), and 77.1 days (TOI-561 e) and a fifth non-transiting candidate, TOI-561f with a period of 433 days.

The precise characterisation of TOI-561’s orbital architecture is interesting since old and metal-poor thick disk stars are less likely to host ultra-short 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 days, thanks to the new CHEOPS and TESS transits.

The new data allowed us to improve its radius (Rp=2.517±0.045R⊕ from 5% to 2% precision) and mass (Mp=12.4±1.4M⊕) estimates, implying a density of ρp=0.778±0.097ρ⊕.

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-minute 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.

Mass-Radius diagram for TOI-561 system. The data are taken from the Extrasolar Planets Encyclopaedia catalog (http://exoplanet. eu/catalog/) as of May 2024. The TOI-561 planets are labeled and updated with the analysis in the current work. The theoretical mass-radius relationship as a function of the chemical composition (Zeng et al. 2019) are shown in dashed colored lines. The shaded grey region represents the forbidden region predicted by collisional stripping (Marcus et al. 2010) — astro-ph.EP

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, T. G. Wilson, Y. Alibert, V. Adibekyan, A. Bonfanti, R. Luque, N. C. Santos, M. J. Hooton, L. Fossati, L. M. Serrano, A. M. S. Smith, S. 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, 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, C. Mordasini, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, M. Stalport, S. Sulis, Gy. M. Szabó, S. Udry, S. Ulmer-Moll, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton

Comments: 13 pages, 10 Figures. Accepted on MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2410.18169 [astro-ph.EP] (or arXiv:2410.18169v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2410.18169
Focus to learn more
Submission history
From: Tiziano Zingales
[v1] Wed, 23 Oct 2024 18:00:00 UTC (9,784 KB)
https://arxiv.org/abs/2410.18169

Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

Follow on Twitter
MORE FROM Exoplanetology: Exoplanets & Exomoons