A super-Earth and a sub-Neptune orbiting the bright, quiet M3 dwarf TOI-1266

Publication date: 
Main author: 
Demory, B. -O.
IAA authors: 
Suárez, J. C.
Demory, B. -O.;Pozuelos, F. J.;Gómez Maqueo Chew, Y.;Sabin, L.;Petrucci, R.;Schroffenegger, U.;Grimm, S. L.;Sestovic, M.;Gillon, M.;McCormac, J.;Barkaoui, K.;Benz, W.;Bieryla, A.;Bouchy, F.;Burdanov, A.;Collins, K. A.;de Wit, J.;Dressing, C. D.;Garcia, L. J.;Giacalone, S.;Guerra, P.;Haldemann, J.;Heng, K.;Jehin, E.;Jofré, E.;Kane, S. R.;Lillo-Box, J.;Maigné, V.;Mordasini, C.;Morris, B. M.;Niraula, P.;Queloz, D.;Rackham, B. V.;Savel, A. B.;Soubkiou, A.;Srdoc, G.;Stassun, K. G.;Triaud, A. H. M. J.;Zambelli, R.;Ricker, G.;Latham, D. W.;Seager, S.;Winn, J. N.;Jenkins, J. M.;Calvario-Velásquez, T.;Franco Herrera, J. A.;Colorado, E.;Cadena Zepeda, E. O.;Figueroa, L.;Watson, A. M.;Lugo-Ibarra, E. E.;Carigi, L.;Guisa, G.;Herrera, J.;Sierra Díaz, G.;Suárez, J. C.;Barrado, D.;Batalha, N. M.;Benkhaldoun, Z.;Chontos, A.;Dai, F.;Essack, Z.;Ghachoui, M.;Huang, C. X.;Huber, D.;Isaacson, H.;Lissauer, J. J.;Morales-Calderón, M.;Robertson, P.;Roy, A.;Twicken, J. D.;Vanderburg, A.;Weiss, L. M.
Astronomy and Astrophysics
Publication type: 
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<SUB>-0.12</SUB><SUP>+0.16</SUP> R<SUB>⊕</SUB> and an orbital period of 10.9 days. The outer, smaller planet has a radius of R = 1.56<SUB>-0.13</SUB><SUP>+0.15</SUP> R<SUB>⊕</SUB> 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 M<SUB>p</SUB> = 13.5<SUB>-9.0</SUB><SUP>+11.0</SUP> M<SUB>⊕</SUB> (&lt;36.8 M<SUB>⊕</SUB> at 2-σ) for TOI-1266 b and 2.2<SUB>-1.5</SUB><SUP>+2.0</SUP> M<SUB>⊕</SUB> (&lt;5.7 M<SUB>⊕</SUB> at 2-σ) for TOI-1266 c. We find small but non-zero orbital eccentricities of 0.09<SUB>-0.05</SUB><SUP>+0.06</SUP> (&lt;0.21 at 2-σ) for TOI-1266 b and 0.04 ± 0.03 (&lt; 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.
ADS Bibcode: 
instrumentation: detectors;planets and satellites: detection;Astrophysics - Earth and Planetary Astrophysics