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Characterising TOI-732 b and c: new insights into the M-dwarf radius and density valley
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| Published in: | Astronomy and astrophysics year:2024; elocationid:A66; month:02; volume:682; extent:28; pages:1-28; 682(2024) vom: Feb., Artikel-ID A66, Seite 1-28 |
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| Authors and Corporations: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
| Other Authors: | Brady, M. [Author] • Wilson, T. G. [Author] • Venturini, J. [Author] • Egger, J. A. [Author] • Brandeker, A. [Author] • Sousa, S. G. [Author] • Lendl, M. [Author] • Simon, A. E. [Author] • Queloz, D. [Author] • Olofsson, G. [Author] • Adibekyan, V. [Author] • Alibert, Y. [Author] • Fossati, L. [Author] • Hooton, M. J. [Author] • Kubyshkina, D. [Author] • Luque, R. [Author] • Murgas, F. [Author] • Mustill, A. J. [Author] • Santos, N. C. [Author] • Grootel, V. Van [Author] • Alonso, R. [Author] • Asquier, J. [Author] • Bandy, T. [Author] • Bárczy, T. [Author] • Navascues, D. Barrado [Author] • Barros, S. C. C. [Author] • Baumjohann, W. [Author] • Bean, J. [Author] • Beck, M. [Author] • Beck, T. [Author] • Benz, W. [Author] • Bergomi, M. [Author] • Billot, N. [Author] • Borsato, L. [Author] • Broeg, C. [Author] • Cameron, A. Collier [Author] • Csizmadia, Sz [Author] • Cubillos, P. E. [Author] • Davies, M. B. [Author] • Deleuil, M. [Author] • Deline, A. [Author] • Delrez, L. [Author] • Demangeon, O. D. S. [Author] • Demory, B.-O. [Author] • Ehrenreich, D. [Author] • Erikson, A. [Author] • Fortier, A. [Author] • Fridlund, M. [Author] • Gandolfi, D. [Author] • Gillon, M. [Author] • Güdel, M. [Author] • Günther, M. N. [Author] • Heitzmann, A. [Author] • Helling, Ch [Author] • Hoyer, S. [Author] • Isaak, K. G. [Author] • Kasper, D. [Author] • Kiss, L. L. [Author] • Lam, K. W. F. [Author] • Laskar, J. [Author] • Etangs, A. Lecavelier des [Author] • Magrin, D. [Author] • Maxted, P. F. L. [Author] • Mordasini, C. [Author] • Nascimbeni, V. [Author] • Ottensamer, R. [Author] • Pagano, I. [Author] • Pallé, E. [Author] • Peter, G. [Author] • Piotto, G. [Author] • Pollacco, D. [Author] • Ragazzoni, R. [Author] • Rando, N. [Author] • Rauer, H. [Author] • Ribas, I. [Author] • Scandariato, G. [Author] • Ségransan, D. [Author] • Seifahrt, A. [Author] • Smith, A. M. S. [Author] • Stalport, M. [Author] • Stefánsson, G. [Author] • Steinberger, M. [Author] • Stürmer, Julian [Author] • Szabó, Gy M. [Author] • Thomas, N. [Author] • Udry, S. [Author] • Villaver, E. [Author] • Walton, N. A. [Author] • Westerdorff, K. [Author] • Zingales, T. [Author] |
| Type of Resource: | E-Book Component Part |
| Language: | English |
| published: |
February 2024
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| Series: |
Astronomy and astrophysics, 682(2024) vom: Feb., Artikel-ID A66, Seite 1-28
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| Source: | Verbunddaten SWB Lizenzfreie Online-Ressourcen |
| ISSN: | 1432-0746 |
| Summary: | Context. TOI-732 is an M dwarf hosting two transiting planets that are located on the two opposite sides of the radius valley. Inferring a reliable demographics for this type of systems is key to understanding their formation and evolution mechanisms. Aims. By doubling the number of available space-based observations and increasing the number of radial velocity (RV) measurements, we aim at refining the parameters of TOI-732 b and c. We also use the results to study the slope of the radius valley and the density valley for a well-characterised sample of M-dwarf exoplanets. Methods. We performed a global Markov chain Monte Carlo analysis by jointly modelling ground-based light curves and CHEOPS and TESS observations, along with RV time series both taken from the literature and obtained with the MAROON-X spectrograph. The slopes of the M-dwarf valleys were quantified via a support vector machine (SVM) procedure. Results. TOI-732b is an ultrashort-period planet (P = 0.76837931-0.00000042+0.0000039 days) with a radius Rb = 1.325-0.058+0.057R⊕, a mass Mb = 2.46 ± 0.19 M⊕, and thus a mean density ρb = 5.8-0.8+1.0 g cm-3, while the outer planet at P = 12.252284 ± 0.000013 days has Rc = 2.39-0.11+0.10R⊕, Mc = 8.04-0.48+0.50M⊕, and thus ρc = 3.24-0.43+0.55 g cm-3. Even with respect to the most recently reported values, this work yields uncertainties on the transit depths and on the RV semi-amplitudes that are smaller up to a factor of ~1.6 and ~2.4 for TOI-732 b and c, respectively. Our calculations for the interior structure and the location of the planets in the mass-radius diagram lead us to classify TOI-732 b as a super-Earth and TOI-732 c as a mini-Neptune. Following the SVM approach, we quantified d log Rp,valley / d logP = -0.065-0.013+0.024, which is flatter than for Sun-like stars. In line with former analyses, we note that the radius valley for M-dwarf planets is more densely populated, and we further quantify the slope of the density valley as d log ρ^valley / d log P = -0.02-0.04+0.12. Conclusions. Compared to FGK stars, the weaker dependence of the position of the radius valley on the orbital period might indicate that the formation shapes the radius valley around M dwarfs more strongly than the evolution mechanisms. |
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| Item Description: |
Online veröffentlicht: 06. Februar 2024 Gesehen am 07.08.2024 |
| Physical Description: |
Illustrationen 28 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/202348180 |