An M dwarf accompanied by a close-in giant orbiter with SPECULOOS

Abstract

In the last decade, a dozen close-in giant planets have been discovered orbiting stars with spectral types ranging from M0 to M4, a mystery since known formation pathways do not predict the existence of such systems. Here, we confirm TOI-4860 b, a Jupiter-sized planet orbiting an M4.5 host, a star at the transition between fully and partially convective interiors. First identified with TESS data, we validate the transiting companion's planetary nature through multicolour photometry from the TRAPPIST-South/North, SPECULOOS, and MuSCAT3 facilities. Our analysis yields a radius of $0.76\pm 0.02{\mathrm{R}}_{\mathrm{Jup}}$ for the planet, a mass of $0.34{\mathrm{M}}_{\odot }$ for the star, and an orbital period of 1.52 d. Using the newly commissioned SPIRIT InGaAs camera at the SPECULOOS-South Observatory, we collect infrared photometry in zYJ that spans the time of secondary eclipse. These observations do not detect a secondary eclipse, placing an upper limit on the brightness of the companion. The planetary nature of the companion is further confirmed through high-resolution spectroscopy obtained with the IRD spectrograph at Subaru Telescope, from which we measure a mass of $0.67\pm 0.14{\mathrm{M}}_{\mathrm{Jup}}$ . Based on its overall density, TOI-4860 b appears to be rich in heavy elements, like its host star.

arXiv commentAccepted for publication in MNRAS Letters

References in corpus (63)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• dynesty: A Dynamic Nested Sampling Package for Estimating Bayesian Posteriors and Evidences
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• The Revised TESS Input Catalog and Candidate Target List
• The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b
• Theoretical Transmission Spectra During Extrasolar Giant Planet Transits
• The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars
• The Mass Dependence Between Protoplanetary Disks and their Stellar Hosts
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• An Infrared Spectroscopic Sequence of M, L and T Dwarfs
• Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
• A Temperature and Abundance Retrieval Method for Exoplanet Atmospheres
• A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization
• Homogeneous studies of transiting extrasolar planets. IV. Thirty systems with space-based light curves
• Towards a deterministic model of planetary formation. III. Mass distribution of short-period planets around stars of various masses
• Core-Accretion Model Predicts Few Jovian-Mass Planets Orbiting Red Dwarfs
• The Mass-Metallicity Relation for Giant Planets
• Giant Planets at Small Orbital Distances
• OGLE 2003-BLG-235/MOA 2003-BLG-53: A planetary microlensing event
• How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_{\odot }$
• M-Subdwarfs: Spectroscopic Classification and the Metallicity Scale
• 3.6 and 4.5 Micron Phase Curves and Evidence for Non-Equilibrium Chemistry in the Atmosphere of Extrasolar Planet HD 189733b
• Low-Mass Dwarf Template Spectra from the Sloan Digital Sky Survey
• A Planetary Companion to the Nearby M4 Dwarf, Gliese 876
• A Spectroscopic Catalog of the Brightest (J<9) M Dwarfs in the Northern Sky
• LDTk: Limb Darkening Toolkit
• Warm Jupiters are less lonely than hot Jupiters: close neighbours
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Prospecting in late-type dwarfs: a calibration of infrared and visible spectroscopic metallicities of late-K and M dwarfs spanning 1.5 dex
• Binaries and the L Dwarf/T Dwarf Transition
• Spectroscopy of New High Proper Motion Stars in the Northern Sky. I. New Nearby Stars, New High Velocity Stars, and an Enhanced Classification Scheme for M Dwarfs
• Extrasolar planet population synthesis III. Formation of planets around stars of different masses
• The Factory and The Beehive II. Activity and Rotation in Praesepe and the Hyades
• The HARPS search for southern extra-solar planets XIX. Characterization and dynamics of the GJ876 planetary system
• HATS-6b: A Warm Saturn Transiting an Early M Dwarf Star, and a Set of Empirical Relations for Characterizing K and M Dwarf Planet Hosts
• Connecting Giant Planet Atmosphere and Interior Modeling: Constraints on Atmospheric Metal Enrichment
• WASP-80b: a gas giant transiting a cool dwarf
• SPECULOOS -- Ultracool Dwarf Transit Survey: Target List and Strategy
• LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission
• Flux calibration of medium-resolution spectra from 300 nm to 2500 nm: Model reference spectra and telluric correction
• Prospecting in Ultracool Dwarfs: Measuring the Metallicities of Mid- and Late-M Dwarfs
• The occurrence rate of giant planets orbiting low-mass stars with TESS
• TESS Hunt for Young and Maturing Exoplanets (THYME) VI: an 11 Myr giant planet transiting a very low-mass star in Lower Centaurus Crux
• Evidence for Hidden Nearby Companions to Hot Jupiters
• Two temperate super-Earths transiting a nearby late-type M dwarf
• A Tendency Toward Alignment in Single-Star Warm Jupiter Systems
• prose: A Python framework for modular astronomical images processing
• Precision radial velocity measurements by the forward-modeling technique in the near-infrared
• Discovery of three new transiting hot Jupiters: WASP-161 b, WASP-163 b and WASP-170 b
• WASP-23b: a transiting hot Jupiter around a K dwarf and its Rossiter-McLaughlin effect
• TOI-5205 b: A Short-period Jovian Planet Transiting a Mid-M Dwarf
• DREAM II. The spin-orbit angle distribution of close-in exoplanets under the lens of tides
• An Eclipsing Substellar Binary in a Young Triple System discovered by SPECULOOS
• Characterizing the Cool KOIs. VII. Refined Physical Properties of the Transiting Brown Dwarf LHS 6343 C
• TOI-3235 b: a transiting giant planet around an M4 dwarf star
• TOI-519 b: a short-period substellar object around an M dwarf validated using multicolour photometry and phase curve analysis
• TOI-3984 A b and TOI-5293 A b: two temperate gas giants transiting mid-M dwarfs in wide binary systems
• HD 28109 hosts a trio of transiting Neptunian planets including a near-resonant pair, confirmed by ASTEP from Antarctica
• ESPRESSO Mass determination of TOI-263b: An extreme inhabitant of the brown dwarf desert
• A low-mass eclipsing binary within the fully convective zone from the NGTS
• In-situ enrichment in heavy elements of hot Jupiters

Cited by in corpus (9)

• Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation
• TOI-5344 b: A Saturn-like planet orbiting a super-Solar metallicity M0 dwarf
• Hundreds of TESS exoplanets might be larger than we thought
• MANGOS II: Five new giant planets orbiting low-mass stars
• SPECULOOS: five years hunting terrestrial planets around ultra-cool dwarfs
• Homogeneous search for spot transits in Kepler and TESS photometry of K $-$ M-type main-sequence stars
• Warm Jupiters around M-dwarfs are great opportunities for extensive chemical, cloud and haze characterisation with JWST
• Cloudy solutions for the clear skies of WASP-80b: 3D cloud feedback on the atmosphere and spectra of a warm Jupiter
• Searching for GEMS: Three warm Saturns and a super-Jupiter orbiting four early M-dwarfs