TOI-1634 b: an Ultra-Short Period Keystone Planet Sitting Inside the M Dwarf Radius Valley
arXiv:2103.12790 · doi:10.3847/1538-3881/ac0157
Abstract
Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally-driven mass loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short period planet TOI-1634 b ( days, , ) orbiting a nearby M2 dwarf (, , ) and whose size and orbital period sit within the M dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of , which makes TOI-1634 b inconsistent with an Earth-like composition at and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky portion that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of the Earth favors the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with .
27 pages, 13 figures, accepted to AAS journals. Our time series are included as a csv file in the arXiv source files
References in corpus (44)
- The Transiting Exoplanet Survey Satellite
- The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
- Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
- Gaia Early Data Release 3: The astrometric solution
- Gaia Early Data Release 3: Photometric content and validation
- EXOFAST: A fast exoplanetary fitting suite in IDL
- How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
- Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
- The H emission of nearby M dwarfs and its relation to stellar rotation
- Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
- Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
- A new list of thorium and argon spectral lines in the visible
- The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres
- Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
- The Solar Neighborhood XXXVII: The Mass-Luminosity Relation for Main Sequence M Dwarfs
- Eclipsing Binary Stars as Benchmarks for Trigonometric Parallaxes in the Gaia Era
- Magnetic activity in the HARPS M-dwarf sample. The rotation-activity relationship for very low-mass stars through R'HK
- Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics
- Observable Consequences of Planet Formation Models in Systems with Close-in Terrestrial Planets
- Predictions of the atmospheric composition of GJ 1132b
- HAZMAT I: The Evolution of Far-UV and Near-UV Emission from Early M Stars
- Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds
- BGLS: A Bayesian formalism for the generalised Lomb-Scargle periodogram
- The Photoeccentric Effect and Proto-Hot Jupiters I. Measuring photometric eccentricities of individual transiting planets
- A Spectroscopic Analysis of the California-Kepler Survey Sample: I. Stellar Parameters, Planetary Radii and a Slope in the Radius Gap
- Kepler-445, Kepler-446 and the Occurrence of Compact Multiples Orbiting Mid-M Dwarf Stars
- Exoplanet secondary atmosphere loss and revival
- A new class of Super-Earths formed from high-temperature condensates: HD219134 b, 55 Cnc e, WASP-47 e
- A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780
- Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain
- Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets
- The HARPS search for southern extra-solar planets XXXV. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543
- Primordial Radius Gap and Potentially Broad Core Mass Distributions of Super-Earths and Sub-Neptunes
- Precise Masses in the WASP-47 System
- MuSCAT2 multicolour validation of TESS candidates: an ultra-short-period substellar object around an M dwarf
- Gaia Search for stellar Companions of TESS Objects of Interest
- A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776
- Precise mass and radius of a transiting super-Earth planet orbiting the M dwarf TOI-1235: a planet in the radius gap?
- A Closer Look at Exoplanet Occurrence Rates: Considering the Multiplicity of Stars Without Detected Planets
- TOI-1235 b: a keystone super-Earth for testing radius valley emergence models around early M dwarfs
- An ultra-short-period transiting super-Earth orbiting the M3 dwarf TOI-1685
- Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)
- Astraea: Predicting Long Rotation Periods with 27-Day Light Curves
- Scaling K2. III. Comparable Planet Occurrence in the FGK Samples of Campaign 5 and Kepler