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

Abstract

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 (Mexico). 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${}_{\oplus }$ and an orbital period of 10.9 days. The outer, smaller planet has a radius of $R=1.56_{-0.13}^{+0.15}$ R${}_{\oplus }$ 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 $M_{\mathrm{p}}$ = $13.5_{-9.0}^{+11.0}$ ${\mathrm{M}}_{\oplus }$ ($<36.8$ ${\mathrm{M}}_{\oplus }$ at 2-$\sigma$) for TOI-1266 b and $2.2_{-1.5}^{+2.0}$ ${\mathrm{M}}_{\oplus }$ ($<5.7$ ${\mathrm{M}}_{\oplus }$ at 2-$\sigma$) for TOI-1266 c. We find small but non-zero orbital eccentricities of $0.09_{-0.05}^{+0.06}$ ($<0.21$ at 2-$\sigma$) for TOI-1266 b and $0.04\pm 0.03$ ($<0.10$ at 2-$\sigma$) for TOI-1266 c. The equilibrium temperatures of both planets are of $413\pm 20$ K and $344\pm 16$ 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.

In press. Accepted for publication in Astronomy and Astrophysics on 20 July 2020

References in corpus (41)

• The Transiting Exoplanet Survey Satellite
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Astrophysics Source Code Library
• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• Mass-Radius Relationships for Solid Exoplanets
• Atmospheric Escape from Hot Jupiters
• The effect of red noise on planetary transit detection
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• Kepler Flares I. Active and Inactive M dwarfs
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• Transit Least Squares: Optimized transit detection algorithm to search for periodic transits of small planets
• Tidal Locking of Habitable Exoplanets
• A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
• Eclipsing Binary Stars as Benchmarks for Trigonometric Parallaxes in the Gaia Era
• Hubble PanCET: An extended upper atmosphere of neutral hydrogen around the warm Neptune GJ 3470 b
• Hot Jupiters in binary star systems
• The Gaia-Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age
• Trends in Atmospheric Properties of Neptune-Size Exoplanets
• Stellar parameters and chemical abundances of 223 evolved stars with and without planets
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• The L 98-59 System: Three Transiting, Terrestrial-Sized Planets Orbiting a Nearby M-dwarf
• The GENGA Code: Gravitational Encounters in N-body simulations with GPU Acceleration
• Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations
• Stellar parameters of early M dwarfs from ratios of spectral features at optical wavelengths
• Detection of Stars within $\sim$0.8 arcseconds of Kepler Objects of Interest
• Testing exoplanet evaporation with multi-transiting systems
• The sub-Neptune desert and its dependence on stellar type: Controlled by lifetime X-ray irradiation
• Formation, tidal evolution and habitability of the Kepler-186 system
• GJ 273: On the formation, dynamical evolution and habitability of a planetary system hosted by an M dwarf at 3.75 parsec
• Hot, rocky and warm, puffy super-Earths orbiting TOI-402 (HD 15337)
• Evidence for Spin-orbit Alignment in the TRAPPIST-1 System
• Predicting a third planet in the Kepler-47 circumbinary system
• Close-in sub-Neptunes reveal the past rotation history of their host stars: atmospheric evolution of planets in the HD3167 and K2-32 planetary systems
• ShaneAO: wide science spectrum adaptive optics system for the Lick Observatory
• Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy
• Analytic Scattering and Refraction Models for Exoplanet Transit Spectra
• GJ357: A low-mass planetary system uncovered by precision radial-velocities and dynamical simulations
• Transit least-squares survey -- II. Discovery and validation of 17 new sub- to super-Earth-sized planets in multi-planet systems from K2
• Planetary mass-radius relations across the galaxy

Cited by in corpus (61)

• The TESS Objects of Interest Catalog from the TESS Prime Mission
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Habitability and Biosignatures of Hycean Worlds
• Warm terrestrial planet with half the mass of Venus transiting a nearby star
• SPECULOOS -- Ultracool Dwarf Transit Survey: Target List and Strategy
• The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020)
• Transit detection of the long-period volatile-rich super-Earth ${\nu }^2$ Lupi d with $CHEOPS$
• The mass of Beta Pictoris c from Beta Pictoris b orbital motion
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• Two temperate super-Earths transiting a nearby late-type M dwarf
• A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067
• A fading radius valley towards M-dwarfs, a persistent density valley across stellar types
• TOI-1452 b: SPIRou and TESS reveal a super-Earth in a temperate orbit transiting an M4 dwarf
• Hubble Space Telescope transmission spectroscopy for the temperate sub-Neptune TOI-270d: a possible hydrogen-rich atmosphere containing water vapour
• Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076
• Water Condensation Zones around Main Sequence Stars
• The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc
• A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096
• SPECULOOS Northern Observatory: searching for red worlds in the northern skies
• A 1.55 R${}_{\oplus }$ habitable-zone planet hosted by TOI-715, an M4 star near the ecliptic South Pole
• A transit survey to search for planets around hot subdwarfs: I. methods and performance tests on light curves from Kepler, K2, TESS, and CHEOPS
• The Demographics of Terrestrial Planets in the Venus Zone
• A Study of Flares in the Ultra-Cool Regime from SPECULOOS-South
• TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
• The CARMENES search for exoplanets around M dwarfs. Two terrestrial planets orbiting G 264-012 and one terrestrial planet orbiting Gl 393
• Discovery and mass measurement of the hot, transiting, Earth-sized planet GJ 3929 b
• HD 28109 hosts a trio of transiting Neptunian planets including a near-resonant pair, confirmed by ASTEP from Antarctica
• Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
• TESS discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136
• Transit Timing Variations in the three-planet system: TOI-270
• The SHERLOCK pipeline: new exoplanet candidates in the WASP-16, HAT-P-27, HAT-P-26, and TOI-2411 systems
• The LHS 1678 System: Two Earth-Sized Transiting Planets and an Astrometric Companion Orbiting an M Dwarf Near the Convective Boundary at 20 pc
• TOI-2285b: A 1.7 Earth-radius Planet Near the Habitable Zone around a Nearby M Dwarf
• Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
• Near real-time precipitable water vapour monitoring for correcting near-infrared observations using satellite remote sensing
• A massive hot Jupiter orbiting a metal-rich early-M star discovered in the TESS full frame images
• Unveiling $\delta$ Scuti and $\gamma$ Doradus Hybrid Pulsation of HD 53166 and HD 53349 Plus Rich Frequencies in HD 52788 -- Catalogs of 70552 $\delta$ Sct and 8080 $\gamma$ Dor
• TESS discovery of a super-Earth orbiting the M dwarf star TOI-1680
• Planetary companions orbiting the M dwarfs GJ 724 and GJ 3988. A CARMENES and IRD collaboration
• TESS discovery of two super-Earths orbiting the M-dwarf stars TOI-6002 and TOI-5713 near the radius valley
• The AstraLux-TESS high-spatial resolution imaging survey. Search for stellar companions of 215 planet candidates from TESS
• TOI-1749: an M dwarf with a Trio of Planets including a Near-Resonant Pair
• A transiting giant planet in orbit around a 0.2-solar-mass host star
• ATREIDES I. Embarking on a trek across the exo-Neptunian landscape with the TOI-421 system
• Two warm Earth-sized exoplanets and an Earth-sized candidate in the M5V-M6V binary system TOI-2267
• HD 183579b: A Warm Sub-Neptune Transiting a Solar Twin Detected by TESS
• TOI-4336 A b: A temperate sub-Neptune ripe for atmospheric characterization in a nearby triple M-dwarf system
• GPU-based framework for detecting small Solar System bodies in targeted exoplanet surveys
• An extended low-density atmosphere around the Jupiter-sized planet WASP-193 b
• Development of the SPECULOOS exoplanet search project
• Tidally Heated Sub-Neptunes, Refined Planetary Compositions, and Confirmation of a Third Planet in the TOI-1266 System
• MANGOS II: Five new giant planets orbiting low-mass stars
• TOI-1743 b, TOI-5799 b, TOI-5799 c and TOI-6223 b: TESS discovery and validation of four super-Earth to Neptune-sized planets around M dwarfs
• TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star
• Exploring the habitability and interior composition of exoplanets lying within the extended habitable zone
• A transiting rocky super-Earth and a non-transiting sub-Neptune orbiting the M dwarf TOI-771
• SPECULOOS: five years hunting terrestrial planets around ultra-cool dwarfs
• Multi-epoch afterglow rebrightenings in GRB 250129A: Evidence for successive shock interactions
• Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
• Hidden Gems in TESS: sherlock finds two new rocky planets around nearby M dwarfs
• A large sub-Neptune transiting the thick-disk M4V TOI-2406