- Demory, B-O;
- Pozuelos, FJ;
- Chew, Y Gómez Maqueo;
- Sabin, L;
- Petrucci, R;
- Schroffenegger, U;
- Grimm, SL;
- Sestovic, M;
- Gillon, M;
- McCormac, J;
- Barkaoui, K;
- Benz, W;
- Bieryla, A;
- Bouchy, F;
- Burdanov, A;
- Collins, KA;
- de Wit, J;
- Dressing, CD;
- Garcia, LJ;
- Giacalone, S;
- Guerra, P;
- Haldemann, J;
- Heng, K;
- Jehin, E;
- Jofré, E;
- Kane, SR;
- Lillo-Box, J;
- Maigné, V;
- Mordasini, C;
- Morris, BM;
- Niraula, P;
- Queloz, D;
- Rackham, BV;
- Savel, AB;
- Soubkiou, A;
- Srdoc, G;
- Stassun, KG;
- Triaud, AHMJ;
- Zambelli, R;
- Ricker, G;
- Latham, DW;
- Seager, S;
- Winn, JN;
- Jenkins, JM;
- Calvario-Velásquez, T;
- Herrera, JA Franco;
- Colorado, E;
- Zepeda, EO Cadena;
- Figueroa, L;
- Watson, AM;
- Lugo-Ibarra, EE;
- Carigi, L;
- Guisa, G;
- Herrera, J;
- Díaz, G Sierra;
- Suárez, JC;
- Barrado, D;
- Batalha, NM;
- Benkhaldoun, Z;
- Chontos, A;
- Dai, F;
- Essack, Z;
- Ghachoui, M;
- Huang, CX;
- Huber, D;
- Isaacson, H;
- Lissauer, JJ;
- Morales-Calderón, M;
- Robertson, P;
- Roy, A;
- Twicken, JD;
- Vanderburg, A;
- Weiss, LM
We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright (K = 8.8), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four sectors of TESS photometry and data from the newly-commissioned 1-m SAINT-EX telescope located in San Pedro Mártir (México). We also include additional ground-based follow-up photometry as well as high-resolution spectroscopy and high-angular imaging observations. The inner, larger planet has a radius of R = 2.37-0.12+0.16 R and an orbital period of 10.9 days. The outer, smaller planet has a radius of R = 1.56-0.13+0.15 R on an 18.8-day orbit. The data are found to be consistent with circular, co-planar and stable orbits that are weakly influenced by the 2:1 mean motion resonance. Our TTV analysis of the combined dataset enables model-independent constraints on the masses and eccentricities of the planets. We find planetary masses of Mp = 13.5-9.0+11.0 M (<36.8 M at 2-σ) for TOI-1266 b and 2.2-1.5+2.0 M (<5.7 M at 2-σ) for TOI-1266 c. We find small but non-zero orbital eccentricities of 0.09-0.05+0.06 (<0.21 at 2-σ) for TOI-1266 b and 0.04 ± 0.03 (< 0.10 at 2-σ) for TOI-1266 c. The equilibrium temperatures of both planets are of 413 ± 20 and 344 ± 16 K, respectively, assuming a null Bond albedo and uniform heat redistribution from the day-side to the night-side hemisphere. The host brightness and negligible activity combined with the planetary system architecture and favourable planet-to-star radii ratios makes TOI-1266 an exquisite system for a detailed characterisation.