A Habitable-Zone Earth-Sized Planet Rescued from False Positive Status

Abstract

We report the discovery of an Earth-sized planet in the habitable zone of a low-mass star called Kepler-1649. The planet, Kepler-1649 c, is 1.06${}_{-0.10}^{+0.15}$ times the size of Earth and transits its 0.1977 +/- 0.0051 Msun mid M-dwarf host star every 19.5 days. It receives 74 +/- 3 % the incident flux of Earth, giving it an equilibrium temperature of 234 +/- 20K and placing it firmly inside the circumstellar habitable zone. Kepler-1649 also hosts a previously-known inner planet that orbits every 8.7 days and is roughly equivalent to Venus in size and incident flux. Kepler-1649 c was originally classified as a false positive by the Kepler pipeline, but was rescued as part of a systematic visual inspection of all automatically dispositioned Kepler false positives. This discovery highlights the value of human inspection of planet candidates even as automated techniques improve, and hints that terrestrial planets around mid to late M-dwarfs may be more common than those around more massive stars.

arXiv comment11 pages, 3 figures, 1 table. Accepted for publication in ApJL

References in corpus (42)

• Gaia Data Release 2. Summary of the contents and survey properties
• On the variation of the Initial Mass Function
• The Gaia mission
• Analytic Lightcurves for Planetary Transit Searches
• Habitable Zones Around Main-Sequence Stars: New Estimates
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• Most 1.6 Earth-Radius Planets are not Rocky
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Overview of the Kepler Science Processing Pipeline
• The Occurrence Rate of Small Planets around Small Stars
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems
• False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives
• Planetary Candidates Observed by Kepler. VIII. A Fully Automated Catalog With Measured Completeness and Reliability Based on Data Release 25
• Terrestrial Planet Occurrence Rates for the Kepler GK Dwarf Sample
• How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_{\odot }$
• Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2
• The Habitability of Planets Orbiting M-dwarf Stars
• An Earth-sized Planet in the Habitable Zone of a Cool Star
• The Derivation, Properties and Value of Kepler's Combined Differential Photometric Precision
• An Efficient Automated Validation Procedure for Exoplanet Transit Candidates
• The orbital eccentricity of small planet systems
• Planetary Candidates Observed by Kepler. VII. The First Fully Uniform Catalog Based on The Entire 48 Month Dataset (Q1-Q17 DR24)
• Planetary Candidates Observed by Kepler IV: Planet Sample From Q1-Q8 (22 Months)
• Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets
• Planetary Candidates from the First Year of the K2 Mission
• An Increase in the Mass of Planetary Systems around Lower-Mass Stars
• Kepler Planet Occurrence Rates for Mid-Type M Dwarfs as a Function of Spectral Type
• The CARMENES search for exoplanets around M dwarfs. Two temperate Earth-mass planet candidates around Teegarden's Star
• Kepler-445, Kepler-446 and the Occurrence of Compact Multiples Orbiting Mid-M Dwarf Stars
• The First Naked-Eye Superflare Detected from Proxima Centauri
• The Solar Neighborhood XLIV: RECONS Discoveries within 10 Parsecs
• Detection of Potential Transit Signals in 17 Quarters of Kepler Data: Results of the Final Kepler Mission Transiting Planet Search (DR25)
• Identifying Exoplanets with Deep Learning III: Automated Triage and Vetting of TESS Candidates
• Red Dots: A temperate 1.5 Earth-mass planet in a compact multi-terrestrial planet system around GJ1061
• Kepler-108: A Mutually Inclined Giant Planet System
• Kepler-1649b: An Exo-Venus in the Solar Neighborhood
• Re-Evaluating Small Long-Period Confirmed Planets From Kepler

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• Occurrence Rates of Planets Orbiting M Stars: Applying ABC to Kepler DR25, Gaia DR2, and 2MASS Data
• Atmospheric Regimes and Trends on Exoplanets and Brown Dwarfs
• Detectability of Molecular Signatures on TRAPPIST-1e through Transmission Spectroscopy Simulated for Future Space-Based Observatories
• The First Habitable Zone Earth-Sized Planet From TESS II: $Spitzer$ Confirms TOI-700 d
• The Far Ultraviolet M-dwarf Evolution Survey. I. The Rotational Evolution of High-Energy Emissions
• Water Condensation Zones around Main Sequence Stars
• Eccentricity Driven Climate Effects in the Kepler-1649 System
• Certification of quantum states with hidden structure of their bitstrings
• Prebiosignature Molecules Can Be Detected in Temperate Exoplanet Atmospheres with JWST
• A high mutual inclination system around KOI-134 revealed by transit timing variations
• Modeling Atmospheric Ion Escape from Kepler-1649 b and c over Time
• New models of reflection spectra for terrestrial exoplanets: Present and prebiotic Earth orbiting around stars of different spectral types