TESS Hunt for Young and Maturing Exoplanets (THYME) VI: an 11 Myr giant planet transiting a very low-mass star in Lower Centaurus Crux

Abstract

Mature super-Earths and sub-Neptunes are predicted to be $\simeq$Jovian radius when younger than 10 Myr. Thus, we expect to find 5-15$R_{\oplus }$ planets around young stars even if their older counterparts harbor none. We report the discovery and validation of TOI 1227 b, a $0.85\pm 0.05R_J$ (9.5$R_{\oplus }$) planet transiting a very low-mass star ($0.170\pm 0.015M_{\odot }$) every 27.4 days. TOI~1227's kinematics and strong lithium absorption confirm it is a member of a previously discovered sub-group in the Lower Centaurus Crux OB association, which we designate the Musca group. We derive an age of 11$\pm$2 Myr for Musca, based on lithium, rotation, and the color-magnitude diagram of Musca members. The TESS data and ground-based follow-up show a deep (2.5\%) transit. We use multiwavelength transit observations and radial velocities from the IGRINS spectrograph to validate the signal as planetary in nature, and we obtain an upper limit on the planet mass of $\simeq 0.5M_J$. Because such large planets are exceptionally rare around mature low-mass stars, we suggest that TOI 1227 b is still contracting and will eventually turn into one of the more common $<5R_{\oplus }$ planets.

arXiv commentAccepted to the Astronomical Journal. Minor updates during referee process and proofs

References in corpus (141)

• emcee: The MCMC Hammer
• The chemical composition of the Sun
• Modules for Experiments in Stellar Astrophysics (MESA)
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• The USNO-B Catalog
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• The Dartmouth Stellar Evolution Database
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Las Cumbres Observatory Global Telescope Network
• Gaia Early Data Release 3: The astrometric solution
• batman: BAsic Transit Model cAlculatioN in Python
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Fast and scalable Gaussian process modeling with applications to astronomical time series
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• On the Unique Solution of Planet and Star Parameters from an Extrasolar Planet Transit Light Curve
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• Gaia Early Data Release 3: Photometric content and validation
• Kepler planets: a tale of evaporation
• AstroImageJ: Image Processing and Photometric Extraction for Ultra-Precise Astronomical Light Curves (Expanded Edition)
• AstroImageJ: Image Processing and Photometric Extraction for Ultra-Precise Astronomical Light Curves
• A Gaia DR2 view of the Open Cluster population in the Milky Way
• Models of Giant Planet formation with migration and disc evolution
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• Stellar Diameters and Temperatures II. Main Sequence K & M Stars
• Biosignatures from Earth-Like Planets Around M Dwarfs
• BANYAN. XI. The BANYAN $\Sigma$ multivariate Bayesian algorithm to identify members of young associations within 150 pc
• The Role of Core Mass in Controlling Evaporation: the Kepler Radius Distribution and the Kepler-36 Density Dichotomy
• The Radial Velocity Experiment (RAVE): Fifth Data Release
• A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
• The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association
• Analysis of isoplanatic high resolution stellar fields by Starfinder code
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets
• The H$\alpha$ emission of nearby M dwarfs and its relation to stellar rotation
• Improving Stellar and Planetary Parameters of Transiting Planet Systems: The Case of TrES-2
• Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. III. A Consistent 10 Myr Age for the Upper Scorpius OB Association
• Kepler Data Validation I -- Architecture, Diagnostic Tests, and Data Products for Vetting Transiting Planet Candidates
• Exoplanetary Spin-Orbit Alignment: Results from the Ensemble of Rossiter-McLaughlin Observations
• Kepler Data Validation II -- Transit Model Fitting and Multiple-Planet Search
• Real-time processing of the imaging data from the network of Las Cumbres Observatory Telescopes using BANZAI
• Photoevaporation and High-Eccentricity Migration Created the Sub-Jovian Desert
• SkyMapper Southern Survey: Second Data Release (DR2)
• A planet within the debris disk around the pre-main-sequence star AU Microscopii
• SOAR TESS Survey. I: Sculpting of TESS planetary systems by stellar companions
• LDTk: Limb Darkening Toolkit
• Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets
• Gaia Data Release 2: Properties and validation of the radial velocities
• Data analysis recipes: Fitting a model to data
• They are Small Worlds After All: Revised Properties of Kepler M Dwarf Stars and their Planets
• M dwarfs: effective temperatures, radii and metallicities
• The Solar Neighborhood XLV. The Stellar Multiplicity Rate of M Dwarfs Within 25 pc
• Astrophysical supplements to the ASCC-2.5. Ia. Radial velocities of about 55000 stars and mean radial velocities of 516 Galactic open clusters and associations
• K2SC: Flexible systematics correction and detrending of K2 light curves using Gaussian Process regression
• A Neptune-sized transiting planet closely orbiting a 5-10-million-year-old star
• Kepler Planet Occurrence Rates for Mid-Type M Dwarfs as a Function of Spectral Type
• Zodiacal Exoplanets in Time (ZEIT) III: A short-period planet orbiting a pre-main-sequence star in the Upper Scorpius OB Association
• Observable Consequences of Planet Formation Models in Systems with Close-in Terrestrial Planets
• An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs
• TESS Hunt for Young and Maturing Exoplanets (THYME): A planet in the 45 Myr Tucana-Horologium association
• BANYAN. III. Radial velocity, Rotation and X-ray emission of low-mass star candidates in nearby young kinematic groups
• Zodiacal Exoplanets In Time (ZEIT) I: A Neptune-sized planet orbiting an M4.5 dwarf in the Hyades Star Cluster
• Rotation of Low-Mass Stars in Upper Scorpius and Rho Ophiuchus with K2
• Four newborn planets transiting the young solar analog V1298 Tau
• Zodiacal Exoplanets in Time (ZEIT) IV: seven transiting planets in the Praesepe cluster
• Correcting for Telluric Absorption: Methods, Case Studies, and Release of the TelFit Code
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• Obliquities of Kepler Stars: Comparison of Single- and Multiple-Transit Systems
• Placing the spotted T Tauri star LkCa 4 on an HR diagram
• TESS Spots a Compact System of Super-Earths around the Naked-Eye Star HR 858
• New constraints on the planetary system around the young active star AU Mic. Two transiting warm Neptunes near mean-motion resonance
• An empirical template library of stellar spectra for a wide range of spectral classes, luminosity classes, and metallicities using SDSS BOSS spectra
• TESS Hunt for Young and Maturing Exoplanets (THYME) II: A 17 Myr Old Transiting Hot Jupiter in the Sco-Cen Association
• Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 $R_{\oplus }$
• Stars with Photometrically Young Gaia Luminosities Around the Solar System (SPYGLASS) I: Mapping Young Stellar Structures and their Star Formation Histories
• A Candidate Young Massive Planet in Orbit around the Classical T Tauri Star CI Tau
• All-sky Co-moving Recovery Of Nearby Young Members. (ACRONYM) II: The Beta Pictoris Moving Group
• Measuring the Recoverability of Close Binaries in Gaia DR2 with the Robo-AO Kepler Survey
• MN48: a new Galactic bona fide luminous blue variable revealed by Spitzer and SALT
• The VLT/NaCo Large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits: I- Sample definition and characterization
• TESS Hunt for Young and Maturing Exoplanets (THYME) III: a two-planet system in the 400 Myr Ursa Major Group
• Characterizing K2 Candidate Planetary Systems Orbiting Low-Mass Stars II: Planetary Systems Observed During Campaigns 1-7
• Re-examining the membership and origin of the Epsilon Cha association
• A hot Jupiter around the very active weak-line T Tauri star TAP 26
• The stellar population of Sco OB2 revealed by Gaia DR2 data
• Investigating the young AU~Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass
• New Pre-main-Sequence Stars in the Upper Scorpius Subgroup of Sco-Cen
• Self-Consistent Magnetic Stellar Evolution Models of the Detached, Solar-Type Eclipsing Binary EF Aquarii
• Zodiacal Exoplanets in Time (ZEIT) VI: a three-planet system in the Hyades cluster including an Earth-sized planet
• Zodiacal Exoplanets in Time (ZEIT) V: A Uniform Search for Transiting Planets in Young Clusters Observed by K2
• That's How We Roll: The NASA K2 Mission Science Products and Their Performance Metrics
• A warm Jupiter-sized planet transiting the pre-main sequence star V1298 Tau
• Fundamental properties of pre-main sequence stars in young, southern star forming regions: metallicities
• Deflating Super-Puffs: Impact of Photochemical Hazes on the Observed Mass-Radius Relationship of Low Mass Planets
• The K2 M67 Study: Revisiting old friends with K2 reveals oscillating red giants in the open cluster M67
• The secondary eclipses of WASP-19b as seen by the ASTEP 400 telescope from Antarctica
• K2 Discovers a Busy Bee: An Unusual Transiting Neptune Found in the Beehive Cluster
• Spin-orbit alignment of exoplanet systems: ensemble analysis using asteroseismology
• Low False-Positive Rate of Kepler Candidates Estimated From A Combination Of Spitzer And Follow-Up Observations
• Diving Beneath the Sea of Stellar Activity: Chromatic Radial Velocities of the Young AU Mic Planetary System
• Constraints on Planet Occurrence around Nearby Mid-to-Late M Dwarfs from the MEarth Project
• TESS Hunt for Young and Maturing Exoplanets (THYME) V: A Sub-Neptune Transiting a Young Star in a Newly Discovered 250 Myr Association
• The hot Jupiter of the magnetically-active weak-line T Tauri star V830 Tau
• A possibly inflated planet around the bright, young star DS Tuc A
• Flares, Rotation, and Planets of the AU Mic System from TESS Observations
• The magnetic field and accretion regime of CI Tau
• TESS Hunt for Young and Maturing Exoplanets (THYME) IV: Three small planets orbiting a 120 Myr-old star in the Pisces--Eridanus stream
• Cluster Difference Imaging Photometric Survey. II. TOI 837: A Young Validated Planet in IC 2602
• Two young planetary systems around field stars with ages between 20-320 Myr from TESS
• Characterizing Undetected Stellar Companions with Combined Datasets
• ACRONYM III: Radial Velocities for 336 Candidate Young Low-Mass Stars in the Solar Neighborhood, Including 78 Newly Confirmed Young Moving Group Members
• A large moving group within the Lower Centaurus Crux association
• A Relationship Between Stellar Age and Spot Coverage
• Exploring the M-dwarf Luminosity--Temperature--Radius Relationships using Gaia DR2
• K2-260 b: a hot Jupiter transiting an F star, and K2-261 b: a warm Saturn around a bright G star
• Contrast sensitivities in the Gaia Data Release 2
• Constraining the entropy of formation from young transiting planets
• Ground-Based Submillimagnitude CCD Photometry of Bright Stars Using Snapshot Observations
• Thermalizing a telescope in Antarctica: Analysis of ASTEP observations
• The $\mu$ Tau Association: A 60 Myr-Old Coeval Group at 150 pc from the Sun
• The GAPS Programme at TNG XXVIII -- A pair of hot-Neptunes orbiting the young star TOI-942
• The GAPS Programme at TNG XXVII. Reassessment of a young planetary system with HARPS-N: is the hot Jupiter V830 Tau b really there?
• Discovery of a Transiting Adolescent Sub-Neptune Exoplanet with K2
• Three K2 Campaigns Yield Rotation Periods for 1013 Stars in Praesepe
• Proper motions of young stars in Chamaeleon. I. A Virtual Observatory study of spectroscopically confirmed members
• Undetected Binary Stars Cause an Observed Mass Dependent Age Gradient in Upper Scorpius
• A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at Thirty Parsecs
• Evidence for Two Hot Jupiter Formation Paths
• The initial physical conditions of Kepler-36 b & c
• Photospheric properties and fundamental parameters of M dwarfs
• Zodiacal Exoplanets in Time (ZEIT) IX: a flat transmission spectrum and a highly eccentric orbit for the young Neptune K2-25b as revealed by Spitzer
• The Mean Magnetic Field Strength of CI Tau
• TESS Reveals HD 118203 b to be a Transiting Planet
• TOI-942b: A Prograde Neptune in a ~60 Myr old Multi-transiting System
• KELT-24b: A 5M${}_{\mathrm{J}}$ Planet on a 5.6 day Well-Aligned Orbit around the Young V=8.3 F-star HD 93148
• A pixel-level model for event discovery in time-domain imaging
• IGRINS RV: A Precision RV Pipeline for IGRINS Using Modified Forward Modeling in the Near-Infrared
• Dippers from the TESS Full-Frame Images I: The Results of the first 1 year data and Discovery of A Runaway dipper
• Accretion Kinematics in the T Tauri Binary TWA 3A: Evidence for Preferential Accretion onto the TWA 3A Primary

Cited by in corpus (39)

• One year of AU Mic with HARPS: II -- stellar activity and star-planet interaction
• Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets
• TOI-5205 b: A Short-period Jovian Planet Transiting a Mid-M Dwarf
• Mid-to-Late M Dwarfs Lack Jupiter Analogs
• The GAPS Programme with HARPS-N at TNG. XXXVII. A precise density measurement of the young ultra-short period planet TOI-1807 b
• AU Microscopii in the FUV: Observations in Quiescence, During Flares, and Implications for AU Mic b and c
• TESS Hunt for Young and Maturing Exoplanets (THYME) IX: a 27 Myr extended population of Lower-Centaurus Crux with a transiting two-planet system
• A giant planet transiting a 3-Myr protostar with a misaligned disk
• TESS Hunt for Young and Maturing Exoplanets (THYME) VII : Membership, rotation, and lithium in the young cluster Group-X and a new young exoplanet
• A Mini-Neptune from TESS and CHEOPS Around the 120 Myr Old AB Dor member HIP 94235
• An M dwarf accompanied by a close-in giant orbiter with SPECULOOS
• TESS Investigation -- Demographics of Young Exoplanets (TI-DYE) II: a second giant planet in the 17-Myr system HIP 67522
• Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian Processes
• Chronostar. II. Kinematic age and substructure of the Scorpius-Centaurus OB2 association
• The metal-poor atmosphere of a Neptune/Sub-Neptune planet progenitor
• The influence of host star activity evolution on the population of super-Earths and mini-Neptunes
• A Framework for Characterizing Transmission Spectra of Exoplanets with Circumplanetary Rings
• HIP 33609 b: An Eccentric Brown Dwarf Transiting a V=7.3 Rapidly Rotating B-Star
• The TEMPO Survey I: Predicting Yields of the Transiting Exosatellites, Moons, and Planets from a 30-day Survey of Orion with the Nancy Grace Roman Space Telescope
• TOI-4562 b: A highly eccentric temperate Jupiter analog orbiting a young field star
• First Comparative Exoplanetology Within a Transiting Multi-planet System: Comparing the atmospheres of V1298 Tau b and c
• Hundreds of TESS exoplanets might be larger than we thought
• The unusual M-dwarf Warm Jupiter TOI-1899~b: Refinement of orbital and planetary parameters
• The TESS Triple-9 Catalog II: a new set of 999 uniformly-vetted exoplanet candidates
• Observing exoplanets from Antarctica in two colours: Set-up and operation of ASTEP+
• A Search for Exoplanets in Open Clusters and Young Associations based on TESS Objects of Interest
• TOI-837 b: characterisation, formation and evolutionary history of an infant warm Saturn-mass planet
• An early giant planet instability recorded in asteroidal meteorites
• A Low-mass, Pre-main-sequence Eclipsing Binary in the 40 Myr Columba Association -- Fundamental Stellar Parameters and Modeling the Effect of Star Spots
• Star-Crossed Lovers DI Tau A and B: Orbit Characterization and Physical Properties Determination
• The GAPS Programme at TNG. LXV. Precise density measurement of TOI-1430 b, a young planet with an evaporating atmosphere
• TOI-3288 b and TOI-4666 b: two gas giants transiting low-mass stars characterised by NIRPS
• A homogeneous TTV investigation of all TESS systems with a confirmed single transiting planet
• Separated twins or just siblings? A multi-planet system around an M dwarf including a cool sub-Neptune
• A sub-Neptune transiting the young field star HD 18599 at 40 pc
• A search for stellar siblings of the ~ 200 Myr TOI-251b planetary system
• Transit Hunt for Young and Maturing Exoplanets (THYME) VIII: a Pleiades-age association harboring two transiting planetary systems from Kepler
• Twinkle Twinkle Little Star, Roman Sees Where You Are: Predicting Exoplanet Transit Yields in the Rosette Nebula with the Nancy Grace Roman Space Telescope
• Atmospheric characterization of HIP 67522 b with VLT/CRIRES+. VLT/CRIRES+ suggests a heavier planet and hints at deuterium fractionation