TOI-1634 b: an Ultra-Short Period Keystone Planet Sitting Inside the M Dwarf Radius Valley
| Autor: | Cloutier, R., Charbonneau, D., Stassun, K. G., Murgas, F., Mortier, A., Massey, R., Lissauer, J. J., Latham, D. W., Irwin, J., Haywood, R. D., Guerra, P., Girardin, E., Giacalone, S. A., Bosch-Cabot, P., Bieryla, A., Winn, J., Watson, C. A., Vanderspek, R., Udry, S., Tamura, M., Sozzetti, A., Shporer, A., Ségransan, D., Seager, S., Savel, A. B., Sasselov, D., Rose, M., Ricker, G., Rice, K., Quintana, E. V., Quinn, S. N., Piotto, G., Phillips, D., Pepe, F., Pedani, M., Parviainen, H., Palle, E., Narita, N., Molinari, E., Micela, G., McDermott, S., Mayor, M., Matson, R. A., Fiorenzano, A. F. Martinez, Lovis, C., López-Morales, M., Kusakabe, N., Jensen, E. L. N., Jenkins, J. M., Huang, C. X., Howell, S. B., Harutyunyan, A., Fűrész, G., Fukui, A., Esquerdo, G. A., Esparza-Borges, E., Dumusque, X., Dressing, C. D., Di Fabrizio, L., Collins, K. A., Cameron, A. Collier, Christiansen, J. L., Cecconi, M., Buchhave, L. A., Boschin, W., Andreuzzi, G. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-3881/ac0157 |
| Popis: | Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally-driven mass loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short period planet TOI-1634 b ($P=0.989$ days, $F=121 F_{\oplus}$, $r_p = 1.790^{+0.080}_{-0.081} R_{\oplus}$) orbiting a nearby M2 dwarf ($K_s=8.7$, $R_s=0.45 R_{\odot}$, $M_s=0.50 M_{\odot}$) and whose size and orbital period sit within the M dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of $4.91^{+0.68}_{-0.70} M_{\oplus}$, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma$ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky portion that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of the Earth favors the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with $M_s\lesssim 0.5 M_{\odot}$. Comment: 27 pages, 13 figures, accepted to AAS journals. Our time series are included as a csv file in the arXiv source files |
| Databáze: | arXiv |
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