The Occurrence Rate of Terrestrial Planets Orbiting Nearby Mid-to-late M Dwarfs from TESS Sectors 1-42

Abstract

We present an analysis of a volume-complete sample of 363 mid-to-late M dwarfs within 15 pc of the Sun with masses between 0.1 and 0.3 M${}_{\odot }$ observed by TESS within Observation Sectors 1 to 42. The median mass of the stars in this sample is 0.17 M${}_{\odot }$. We search the TESS 2-minute cadence light curves for transiting planets with orbital periods below 7 days using a modified Box-Least Squares (BLS) algorithm and recover all 6 known planets within the sample as well as a likely planet candidate orbiting LHS 475 (TESS Object of Interest 910.01). Each of these planets is consistent with a terrestrial composition, with planet radii ranging from 0.91 R${}_{\oplus }$ to 1.31 R${}_{\oplus }$. In addition, we perform a transit injection and recovery analysis for each of the 363 stars to characterize the transit detection sensitivity as a function of planet radius, insolation, and orbital period. We obtain a cumulative occurrence rate of $0.61_{-0.19}^{+0.24}$ terrestrial planets per M dwarf with radii above 0.5 R${}_{\oplus }$ and orbital periods between 0.4-7 days. We find that for comparable insolations, planets larger than 1.5 R${}_{\oplus }$ (sub-Neptunes and water worlds) are significantly less abundant around mid-to-late M dwarfs compared to earlier-type stars, while the occurrence rate of terrestrial planets is comparable to that of more massive M dwarfs. We estimate that overall, terrestrials outnumber sub-Neptunes around mid-to-late M dwarfs at a ratio of 14 to 1, in contrast to GK dwarfs where they are roughly equinumerous. We place a $1\sigma$ upper limit of 0.07 planets larger than 1.5 R${}_{\oplus }$ per mid-to-late M dwarf, within the orbital period range of 0.5-7 days. We find evidence for a downturn in occurrence rates for planet radii below 0.9 R${}_{\oplus }$, suggesting that Earth-sized and larger terrestrials may be more common around mid-to-late M dwarfs.

25 pages, 8 figures, 9 tables. Accepted for publication in the Astronomical Journal

References in corpus (21)

• Most 1.6 Earth-Radius Planets are not Rocky
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• A stellar-mass-dependent drop in planet occurrence rates
• Density, not radius, separates rocky and water-rich small planets orbiting M dwarf stars
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• Formation of planetary systems by pebble accretion and migration: How the radial pebble flux determines a terrestrial-planet or super-Earth growth mode
• Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• The CARMENES search for exoplanets around M dwarfs -- Planet occurrence rates from a subsample of 71 stars
• Why do M dwarfs have more transiting planets?
• A More Precise Mass for GJ 1214 b and the Frequency of Multi-Planet Systems Around Mid-M Dwarfs
• A Joint Mass-Radius-Period Distribution of Exoplanets
• A Second Planet Transiting LTT 1445A and a Determination of the Masses of Both Worlds
• Predicting the Exoplanet Yield of the TESS Prime and Extended Missions Through Years 1-7
• The Volume-Complete Sample of M Dwarfs with Masses 0.1 <= M/M_sol <= 0.3 within 15 Parsecs
• An Increase in Small-planet Occurrence with Metallicity for Late-type Dwarf Stars in the Kepler Field and Its Implications for Planet Formation
• TOI 540 b: A Planet Smaller than Earth Orbiting a Nearby Rapidly Rotating Low-mass Star
• Assessing $TESS$'s Yield of Rocky Planets Around Nearby M Dwarfs
• A Distinct Population of Small Planets: Sub-Earths
• Host Star Dependence of Small Planet Mass-Radius Distributions

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• A JWST transmission spectrum of a nearby Earth-sized exoplanet
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• Super-Earths and Earth-like Exoplanets
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• Chromaticity of stellar activity in radial velocities : Anti-correlated families of lines on the M dwarf EV Lac with SPIRou and SOPHIE
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• On the diversification and dissipation of protoplanetary disks
• Scaling K2 VIII: Short-Period Sub-Neptune Occurrence Rates Peak Around Early-Type M Dwarfs
• The corona of a fully convective star with a near-polar flare
• The Solar Neighborhood LII: M Dwarf Twin Binaries -- Presumed Identical Twins Appear Fraternal in Variability, Rotation, H$\alpha$, and X-rays
• Characterizing planetary systems with SPIRou: Detection of a sub-Neptune in a 6-day period orbit around the M dwarf Gl 410
• Quantifying the Effect of Short-timescale Stellar Activity Upon Transit Detection in M Dwarfs
• Radial velocity homogeneous analysis of M dwarfs observed with HARPS. II. Detection limits and planetary occurrence statistics
• Modern Earth-like Chemical Disequilibrium Biosignatures Are Challenging To Constrain Through Spectroscopic Retrievals
• The Solar Neighborhood. LV. M Dwarf Twin Binaries -- One in Five Twin Sibling Pairs Are Mismatched in Activity and/or Rotation
• Densities of small planets around the M dwarfs TOI-4336 A and TOI-4342 with ESPRESSO: Three sub-Neptunes, one super-Earth, and a Neptune-mass candidate
• Resistive MHD Simulations of Stellar Wind-Magnetosphere Coupling in TRAPPIST-1e