A team of international astronomers reported on the discovery of one super-Earth- (TOI-1749b) and two sub-Neptune-sized planets (TOI1749c and TOI-1749d) transiting an early M dwarf TOI-1749 at a distance of 100 pc. Their study recently appeared in Arxiv.
Astronomers first identified these systems as planetary candidates using data from the TESS photometric survey. Later, they have followed up this system from the ground by means of multiband transit photometry, adaptive-optics imaging, and low-resolution spectroscopy, from which they have validated the planetary nature of the candidates.
They found that TOI-1749 b, c, and d have orbital periods of 2.39, 4.49, and 9.05 days, and radii of 1.4, 2.1, and 2.5 R, respectively. (More derived parameters are given in Table 1 below)
In addition, using photodynamical models they have been able to place 95% confidence level upper limits on the masses of TOI-1749b, TOI-1749c, and TOI-1749d of 57, 14, and 15 M, respectively.
The periods, sizes, and tentative masses of these planets are in line with a scenario in which all three planets initially had a hydrogen envelope on top of a rocky core, and only the envelope of the innermost planet has been stripped away by photoevaporation and/or core-powered mass loss mechanisms.
“The compositions of the innermost planet and the outer two planets can be explained by a bare rocky core and a rocky core + thin hydrogen envelope respectively.”
In addition, they have confirmed that the system is dynamically stable for at least 109 orbits of the innermost planet.
The outer planetary pair has a period ratio very close to the 2:1 commensurability (2.015), sharing the orbital architecture with the other M dwarf systems TOI-270 and TOI-175. This characteristic architecture might be a consequence of common planetary formation and migration processes in these systems.
“Further follow-up observations of this system would be worth pursuing to characterize the system in more detail.”— concluded authors of the study
Featured image credit: Getty Images
Reference: A. Fukui, J. Korth, J. H. Livingston, J. D. Twicken, M. R. Zapatero Osorio, J. M. Jenkins, M. Mori, F. Murgas, M. Ogihara, N. Narita, E. Pallé, K. G. Stassun, G. Nowak, D. R. Ciardi, L. Alvarez-Hernandez, V. J. S. Béjar, N. Casasayas-Barris, N. Crouzet, J. P. de Leon, E. Esparza-Borges, D. Hidalgo Soto, K. Isogai, K. Kawauchi, P. Klagyivik, T. Kodama, S. Kurita, N. Kusakabe, R. Luque, A. Madrigal-Aguado, P. Montanes Rodriguez, G. Morello, T. Nishiumi, J. Orell-Miquel, M. Oshagh, H. Parviainen, M. Sánchez-Benavente, M. Stangret, N. Watanabe, G. Chen, M. Tamura, P. Bosch-Cabot, M. Bowen, K. Eastridge, L. Freour, E. Gonzales, P. Guerra, Y. Jundiyeh, T. K. Kim, L. V. Kroer, A. M. Levine, E. H. Morgan, M. Reefe, R. Tronsgaard, C. K. Wedderkopp, J. Wittrock, K. A. Collins, K. Hesse, D. W. Latham, G. R. Ricker, S. Seager, R. Vanderspek, J. Winn, E. Bachelet, M. Bowman, C. McCully, M. Daily, D. Harbeck, N. H. Volgenau, “TOI-1749: an M dwarf with a Trio of Planets including a Near-Resonant Pair”, Arxiv, pp. 1-30, 2021. https://arxiv.org/abs/2107.05430
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