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

Abstract

Full list of authors: 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. ; 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. © 2020 ESO. ; We warmly thank the entire technical staff of the Observatorio Astronomico Nacional at San Pedro Martir in Mexico for their unfailing support to SAINT-EX operations, namely: U. Cesena, A. Cordova, B. Garcia, C.A. Guerrero, F. Guillen, J.A. Hernandez, B. Hernandez, E. Lopez, B. Martinez, G. Melgoza, F. Montalvo, S. Monrroy,J.C. Narvaez, J.M. Nunez, J.L. Ochoa, I. Plauchu, F. Quiroz, H. Serrano, T. Verdugo. We gratefully acknowledgethe support from the Embassy of Mexico in Bern to the SAINT-EX project. We also thank the past members of the SAINT-EX team B. Courcol, E. Rose and K. Housen for their help in the course of the project. We are grateful to the anonymous referee for a thorough and helpful review of our paper. We thank Jonathan Irwin for his help on the TRES data analysis. B.-O.D. acknowledges support from the Swiss National Science Foundation (PP00P2-163967). This work has been carried out within the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation. Y.G.M.C acknowledges support from UNAM-PAPIIT IN-107518. R.P. and E.J. acknowledge DGAPA for their postdoctoral fellowships. The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fonds National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Fundation (SNF). TRAPPIST-North is a project funded by the University of Liege, and performed in collaboration with Cadi Ayyad University of Marrakesh. M.G. and E.J. are F.R.S.-FNRS Senior Research Associates. J.C.S. acknowledges funding support from Spanish public funds for research under projects ESP2017-87676-2-2 and RYC-2012-09913 (Ramon y Cajal programme) of the Spanish Ministry of Science and Education. This paper includes data collected by the TESS mission. We acknowledge the use of public TOI Release data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Funding for the TESS mission is provided by the NASA Explorer Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This work is based upon observationscarried out at the Observatorio Astronomico Nacional on the Sierra de San Pedro Martir (OAN-SPM), Baja California, Mexico. This research has been partly funded by the Spanish State Research Agency (AEI) Projects No.ESP2017-87676-C5-1-R and No. MDM-2017-0737 Unidad de Excelencia "Maria de Maeztu"- Centro de Astrobiologia (INTA-CSIC). This paper is based on observations collected at Centro Astronomico Hispano en Andalucia (CAHA) at Calar Alto, operated jointly by Instituto de Astrofisica de Andalucia (CSIC) and Junta de Andalucia. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) ERC Grant Agreement n o 336480 (SPECULOOS). D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC18K1585, 80NSSC19K0379), and the National Science Foundation (AST-1717000). We finally acknowledge support from the Antoine de Saint-Exupery Youth Foundation through their involvement in the educational programme of the SAINT-EX Observatory. With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)