A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at Thirty Parsecs

Abstract

We report the discovery of three small transiting planets orbiting GJ 9827, a bright (K = 7.2) nearby late K-type dwarf star. GJ 9827 hosts a $1.62\pm 0.11$ $R_{\oplus }$ super Earth on a 1.2 day period, a $1.269_{-0.089}^{+0.087}$ $R_{\oplus }$ super Earth on a 3.6 day period, and a $2.07\pm 0.14$ $R_{\oplus }$ super Earth on a 6.2 day period. The radii of the planets transiting GJ 9827 span the transition between predominantly rocky and gaseous planets, and GJ 9827 b and c fall in or close to the known gap in the radius distribution of small planets between these populations. At a distance of 30 parsecs, GJ 9827 is the closest exoplanet host discovered by K2 to date, making these planets well-suited for atmospheric studies with the upcoming James Webb Space Telescope. The GJ 9827 system provides a valuable opportunity to characterize interior structure and atmospheric properties of coeval planets spanning the rocky to gaseous transition.

arXiv comment9 pages, 4 figures, 3 tables, Accepted to the Astronomical Journal, Improved Global Fit

References in corpus (62)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Validation of the new Hipparcos reduction
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• The James Webb Space Telescope
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• The Dartmouth Stellar Evolution Database
• The K2 Mission: Characterization and Early results
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• Accurate masses and radii of normal stars: modern results and applications
• Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler
• Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
• Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b
• Elemental Abundance Survey of The Galactic Thick Disk
• The NASA Exoplanet Archive: Data and Tools for Exoplanet Research
• Towards Better Age Estimates for Stellar Populations: The Y^2 Isochrones for Solar Mixture
• Prevalence of Earth-size planets orbiting Sun-like stars
• A super-Earth transiting a nearby low-mass star
• Most 1.6 Earth-Radius Planets are not Rocky
• Theoretical Transmission Spectra During Extrasolar Giant Planet Transits
• The evaporation valley in the Kepler planets
• EXOFAST: A fast exoplanetary fitting suite in IDL
• Atmospheric Escape from Hot Jupiters
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Temperate Earth-sized planets transiting a nearby ultracool dwarf star
• Probabilistic Forecasting of the Masses and Radii of Other Worlds
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• Stellar Diameters and Temperatures II. Main Sequence K & M Stars
• The Mass-Radius Relation for 65 Exoplanets Smaller than 4 Earth Radii
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets
• Planetary evaporation by UV & X-ray radiation: basic hydrodynamics
• Mass-Radius Relation for Rocky Planets based on PREM
• Transmission Spectra as Diagnostics of Extrasolar Giant Planet Atmospheres
• Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
• Almost All of Kepler's Multiple Planet Candidates are Planets
• An Efficient Automated Validation Procedure for Exoplanet Transit Candidates
• Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations
• Density and Eccentricity of Kepler Planets
• Kepler Planet Masses and Eccentricities from TTV Analysis
• Planetary Candidates from the First Year of the K2 Mission
• Near-infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs
• 197 Candidates and 104 Validated Planets in K2's First Five Fields
• Prospecting in late-type dwarfs: a calibration of infrared and visible spectroscopic metallicities of late-K and M dwarfs spanning 1.5 dex
• Stellar and Planetary Properties of K2 Campaign 1 Candidates and Validation of 17 Planets, Including a Planet Receiving Earth-like Insolation
• A First Comparison of Kepler Planet Candidates in Single and Multiple Systems
• The Radius Distribution of Planets Around Cool Stars
• On the Indirect Detection of Sodium in the Atmosphere of the Planetary Companion to HD 209458
• Spitzer Observations Confirm and Rescue the Habitable-Zone Super-Earth K2-18b for Future Characterization
• Eleven Multi-planet Systems from K2 Campaigns 1 & 2 and the Masses of Two Hot Super-Earths
• Highlights in the Study of Exoplanet Atmospheres
• Measuring Transit Signal Recovery in the Kepler Pipeline II: Detection Efficiency as Calculated in One Year of Data
• MOST detects transits of HD 97658b, a warm, likely volatile-rich super-Earth
• Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
• Five Planets Transiting a Ninth Magnitude Star
• Two Small Planets Transiting HD 3167
• Three Small Super-Earths Transiting the nearby star GJ 9827
• The Rotation-Activity Correlations in K and M dwarfs. I. Stellar parameters, compilations of $v\sin i$ and $P/\sin i$ for a large sample of late-K and M dwarfs
• KELT-4Ab: An inflated Hot Jupiter transiting the bright (V~10) component of a hierarchical triple
• A Multi-Planet System Transiting the $V$ = 9 Rapidly Rotating F-Star HD 106315
• The K2-ESPRINT Project III: A Close-in Super-Earth around a Metal-rich Mid-M Dwarf
• Two NIRCam channels are Better than One: How JWST Can Do More Science with NIRCam's Short-Wavelength Dispersed Hartmann Sensor

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• Habitability and Biosignatures of Hycean Worlds
• JWST/NIRISS reveals the water-rich "steam world" atmosphere of GJ 9827 d
• TESS Hunt for Young and Maturing Exoplanets (THYME) VI: an 11 Myr giant planet transiting a very low-mass star in Lower Centaurus Crux
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
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• Hot, rocky and warm, puffy super-Earths orbiting TOI-402 (HD 15337)
• A Compact Multi-Planet System With A Significantly Misaligned Ultra Short Period Planet
• Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets
• Near-resonance in a system of sub-Neptunes from TESS
• Caught in the Act: Core-powered Mass-loss Predictions for Observing Atmospheric Escape
• Validation of 13 Hot and Potentially Terrestrial TESS Planets
• A Discrete Set of Possible Transit Ephemerides for Two Long Period Gas Giants Orbiting HIP 41378
• Water absorption in the transmission spectrum of the water-world candidate GJ9827d
• A multi-wavelength look at the GJ 9827 system -- No evidence of extended atmospheres in GJ 9827 b and d from HST and CARMENES data
• Three small planets transiting the bright young field star K2-233
• Mass determination of the 1:3:5 near-resonant planets transiting GJ 9827 (K2-135)
• Physical Parameters of the Multi-Planet Systems HD 106315 and GJ 9827
• Planetary parameters, XUV environments and mass-loss rates for nearby gaseous planets with X-ray detected host-stars
• Non-detection of Helium in the Hot Jupiter WASP-48b
• Absence of extended atmospheres in low-mass star radius-gap planets GJ 9827 b, GJ 9827 d and TOI-1235 b
• K2-280b -- a low density warm sub-Saturn around a mildly evolved star
• $\pi$ Earth: a 3.14-day Earth-sized Planet from $\text{K2}$'s Kitchen Served Warm by the SPECULOOS Team
• A Cool Earth-sized Planet Candidate Transiting a Tenth Magnitude K-dwarf From K2