The CARMENES search for exoplanets around M dwarfs, Wolf 1069 b: Earth-mass planet in the habitable zone of a nearby, very low-mass star

Abstract

We present the discovery of an Earth-mass planet ($M_b\sin i=1.26\pm 0.21M_{\oplus }$) on a 15.6d orbit of a relatively nearby ($d\sim$9.6pc) and low-mass ($0.167\pm 0.011M_{\odot }$) M5.0V star, Wolf 1069. Sitting at a separation of $0.0672\pm 0.0014$au away from the host star puts Wolf 1069b in the habitable zone (HZ), receiving an incident flux of $S=0.652\pm 0.029S_{\oplus }$. The planetary signal was detected using telluric-corrected radial-velocity (RV) data from the CARMENES spectrograph, amounting to a total of 262 spectroscopic observations covering almost four years. There are additional long-period signals in the RVs, one of which we attribute to the stellar rotation period. This is possible thanks to our photometric analysis including new, well-sampled monitoring campaigns undergone with the OSN and TJO facilities that supplement archival photometry (i.e., from MEarth and SuperWASP), and this yielded an updated rotational period range of $P_{rot}=150-170$d, with a likely value at $169.3_{-3.6}^{+3.7}$d. The stellar activity indicators provided by the CARMENES spectra likewise demonstrate evidence for the slow rotation period, though not as accurately due to possible factors such as signal aliasing or spot evolution. Our detectability limits indicate that additional planets more massive than one Earth mass with orbital periods of less than 10 days can be ruled out, suggesting that perhaps Wolf 1069 b had a violent formation history. This planet is also the 6th closest Earth-mass planet situated in the conservative HZ, after Proxima Centauri b, GJ 1061d, Teegarden's Star c, and GJ 1002 b and c. Despite not transiting, Wolf 1069b is nonetheless a very promising target for future three-dimensional climate models to investigate various habitability cases as well as for sub-ms${}^{-1}$ RV campaigns to search for potential inner sub-Earth-mass planets in order to test planet formation theories.

arXiv comment26 pages, 15 figures

References in corpus (113)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Gaia Data Release 3: Summary of the content and survey properties
• The Transiting Exoplanet Survey Satellite
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• dynesty: A Dynamic Nested Sampling Package for Estimating Bayesian Posteriors and Evidences
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Habitable Zones Around Main-Sequence Stars: New Estimates
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Bayes in the sky: Bayesian inference and model selection in cosmology
• The WASP Project and the SuperWASP Cameras
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Fast and scalable Gaussian process modeling with applications to astronomical time series
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• EXOFAST: A fast exoplanetary fitting suite in IDL
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• 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
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• Correcting systematic effects in a large set of photometric lightcurves
• RadVel: The Radial Velocity Modeling Toolkit
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• Late-type stars members of young stellar kinematic groups - I. Single stars
• The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf
• Mass-Radius Relation for Rocky Planets based on PREM
• A dynamically-packed planetary system around GJ667C with three super-Earths in its habitable zone
• Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
• The first WASP public data release
• The H$\alpha$ emission of nearby M dwarfs and its relation to stellar rotation
• Juliet: a versatile modelling tool for transiting and non-transiting exoplanetary systems
• Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
• The Habitability of Planets Orbiting M-dwarf Stars
• Density, not radius, separates rocky and water-rich small planets orbiting M dwarf stars
• The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood
• The habitability of Proxima Centauri b II. Possible climates and Observability
• The CARMENES search for exoplanets around M dwarfs: High-resolution optical and near-infrared spectroscopy of 324 survey stars
• Transit Least Squares: Optimized transit detection algorithm to search for periodic transits of small planets
• 3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability and habitability
• An Increase in the Mass of Planetary Systems around Lower-Mass Stars
• Assessing the Habitability of the TRAPPIST-1 System Using a 3D Climate Model
• Atmospheric escape from the TRAPPIST-1 planets and implications for habitability
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• The CARMENES search for exoplanets around M dwarfs: Different roads to radii and masses of the target stars
• Modelling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets
• The UV and X-ray activity of the M dwarfs within 10pc of the Sun
• Rotation Velocities for M-dwarfs
• A public HARPS radial velocity database corrected for systematic errors
• Magnetism, rotation, and nonthermal emission in cool stars -- Average magnetic field measurements in 292 M dwarfs
• Kepler Planet Occurrence Rates for Mid-Type M Dwarfs as a Function of Spectral Type
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• Tidal obliquity evolution of potentially habitable planets
• The CARMENES search for exoplanets around M dwarfs -- Planet occurrence rates from a subsample of 71 stars
• The CARMENES search for exoplanets around M dwarfs. Two temperate Earth-mass planet candidates around Teegarden's Star
• Four newborn planets transiting the young solar analog V1298 Tau
• Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System
• The M dwarf planet search programme at the ESO VLT + UVES. A search for terrestrial planets in the habitable zone of M dwarfs
• A candidate short-period sub-Earth orbiting Proxima Centauri
• Accounting for velocity jitter in planet search surveys
• Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets
• Habitable Climate Scenarios for Proxima Centauri b With a Dynamic Ocean
• Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars
• Revisiting Proxima with ESPRESSO
• Origin of Earth's water: sources and constraints
• Characterizing Exoplanet Habitability
• Solar System Formation in the Context of Extra-Solar Planets
• CARMENES input catalogue of M dwarfs IV. New rotation periods from photometric time series
• The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths
• The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn
• Occurrence Rates of Planets Orbiting M Stars: Applying ABC to Kepler DR25, Gaia DR2, and 2MASS Data
• Detecting extrasolar planets from stellar radial velocities using Bayesian evidence
• SPECULOOS -- Ultracool Dwarf Transit Survey: Target List and Strategy
• The Solar Neighborhood XXVIII: The Multiplicity Fraction of Nearby Stars from 5 to 70 AU and the Brown Dwarf Desert Around M Dwarfs
• The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020)
• Formation, stratification, and mixing of the cores of Earth and Venus
• The CARMENES search for exoplanets around M dwarfs -- Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multiwavelength range modeling of activity insensitive lines
• A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs
• Bayesian analysis of radial velocity data of GJ667C with correlated noise: evidence for only 2 planets
• The CARMENES search for exoplanets around M dwarfs. Radial velocities and activity indicators from cross-correlation functions with weighted binary masks
• Disentangling Planets and Stellar Activity for Gliese 667C
• GJ 367b: A dense ultra-short period sub-Earth planet transiting a nearby red dwarf star
• A Near-Infrared Spectroscopic Survey of 886 Nearby M Dwarfs
• Monitoring the radio emission of Proxima Centauri
• Exoplanet-induced radio emission from M-dwarfs
• Why do M dwarfs have more transiting planets?
• The AstraLux Multiplicity Survey: Extension to Late M-dwarfs
• The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part I: Dry Cases -- The fellowship of the GCMs
• Two temperate super-Earths transiting a nearby late-type M dwarf
• Ocean Dynamics and the Inner Edge of the Habitable Zone for Tidally Locked Terrestrial Planets
• RV-detected planets around M dwarfs: Challenges for core accretion models
• Red Dots: A temperate 1.5 Earth-mass planet in a compact multi-terrestrial planet system around GJ1061
• NGTS clusters survey. I. Rotation in the young benchmark open cluster Blanco 1
• The New Generation Planetary Population Synthesis (NGPPS). V. Predetermination of planet types in global core accretion models
• The CARMENES search for exoplanets around M dwarfs. Three temperate to warm super-Earths
• Two temperate Earth-mass planets orbiting the nearby star GJ1002
• The impact of pebble flux regulated planetesimal formation on giant planet formation
• Precise mass and radius of a transiting super-Earth planet orbiting the M dwarf TOI-1235: a planet in the radius gap?
• GJ 1252 b: A 1.2 $R_{\oplus }$ planet transiting an M3-dwarf at 20.4 pc
• The CARMENES search for exoplanets around M dwarfs. Mapping stellar activity indicators across the M dwarf domain
• Exomoons in the habitable zones of M dwarfs
• Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)
• Robo-AO M Dwarf Multiplicity Survey: Catalog
• The First Habitable Zone Earth-sized Planet from TESS. III: Climate States and Characterization Prospects for TOI-700 d
• The CARMENES search for exoplanets around M dwarfs: Benchmarking the impact of activity in high-precision radial velocity measurements
• EDEN: Sensitivity Analysis and Transiting Planet Detection Limits for Nearby Late Red Dwarfs
• EUV-driven ionospheres and electron transport on extrasolar giant planets orbiting active stars
• The CARMENES search for exoplanets around M dwarfs. Two terrestrial planets orbiting G 264-012 and one terrestrial planet orbiting Gl 393
• Linking planetary embryo formation to planetesimal formation II: The impact of pebble accretion in the terrestrial planet zone
• Assessing $TESS$'s Yield of Rocky Planets Around Nearby M Dwarfs
• The occurrence rate of exoplanets orbiting ultracool dwarfs as probed by K2
• The CARMENES search for exoplanets around M dwarfs. Diagnostic capabilities of strong K I lines for photosphere and chromosphere
• A target list for searching for habitable exomoons
• Climates of Warm Earth-Like Planets III: Fractional Habitability from a Water Cycle Perspective

Cited by in corpus (16)

• The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020)
• Close-in ice lines and the super-stellar C/O ratio in discs around very low-mass stars
• Water Condensation Zones around Main Sequence Stars
• The CARMENES search for exoplanets around M dwarfs. Telluric absorption corrected high S/N optical and near-infrared template spectra of 382 M dwarf stars
• Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
• TOI-4438 b: a transiting mini-Neptune amenable to atmospheric characterization
• Exploring Climate with Obliquity in a Variable-eccentricity Earth-like World
• Two sub-Neptunes around the M dwarf TOI-1470
• The CARMENES search for exoplanets around M dwarfs. Occurrence rates of Earth-like planets around very low-mass stars
• The CARMENES search for exoplanets around M dwarfs. A sub-Neptunian mass planet in the habitable zone of HN Lib
• Probing the Limits of Habitability: A Catalog of Rocky Exoplanets in the Habitable Zone
• A novel metric for assessing climatological surface habitability
• Snowball Bistability Vanishes at Moderate Orbital Eccentricity
• The climates and thermal emission spectra of prime nearby temperate rocky exoplanet targets
• Exploring stellar activity in a sample of active M dwarfs
• Refined M-type Star Catalog from LAMOST DR10: Measurements of Radial Velocities, $T_{\text{eff}}$, log $g$, [M/H] and [$\alpha$/M]