Three Temperate Neptunes Orbiting Nearby Stars

Abstract

We present the discovery of three modestly-irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of $15.4\pm 2.4$ M${}_{\oplus }$, a semi-major axis of 0.55 AU, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 ($\rho$ CrB). The new planet orbiting HD 164922 has a minimum mass of $12.9\pm 1.6$ M${}_{\oplus }$ and orbits interior to the previously known Jovian mass planet orbiting at 2.1 AU. HD 164922 c has a semi-major axis of 0.34 AU and an equilibrium temperature of 418 K. HD 143761 c orbits with a semi-major axis of 0.44 AU, has a minimum mass of $25\pm 2$ M${}_{\oplus }$, and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically-inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets.

arXiv commentRevisions submitted to ApJ

References in corpus (68)

• The chemical composition of the Sun
• Validation of the new Hipparcos reduction
• The Dartmouth Stellar Evolution Database
• Accurate masses and radii of normal stars: modern results and applications
• Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler
• The false positive rate of Kepler and the occurrence of planets
• Towards a Deterministic Model of Planetary Formation I: a Desert in the Mass and Semi Major Axis Distributions of Extra Solar Planets
• Catalog of Nearby Exoplanets
• The Keck Planet Search: Detectability and the Minimum Mass and Orbital Period Distribution of Extrasolar Planets
• Prevalence of Earth-size planets orbiting Sun-like stars
• No planet for HD 166435
• EXOFAST: A fast exoplanetary fitting suite in IDL
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
• The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters
• The Mass-Radius Relation for 65 Exoplanets Smaller than 4 Earth Radii
• Extrasolar planet population synthesis I: Method, formation tracks and mass-distance distribution
• Asteroseismology of Solar-Type and Red-Giant Stars
• First Results from the CHARA Array. II. A Description of the Instrument
• Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
• Improving the Efficiency of Markov Chain Monte Carlo for Analyzing the Orbits of Extrasolar Planets
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I
• The Minimum-Mass Extrasolar Nebula: In-Situ Formation of Close-In Super-Earths
• The peculiar solar composition and its possible relation to planet formation
• Toward a Deterministic Model of Planetary Formation V. Accumulation Near the Ice Line
• Testing Scaling Relations for Solar-Like Oscillations from the Main Sequence to Red Giants using Kepler Data
• State of the Field: Extreme Precision Radial Velocities
• Friends of Hot Jupiters I: A Radial Velocity Search for Massive, Long-Period Companions to Close-In Gas Giant Planets
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs I. New atmospheric parameters and masses for 48 stars with planets
• Migration then assembly: Formation of Neptune mass planets inside 1 AU
• The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth
• Planetary detection limits taking into account stellar noise. I. Observational strategies to reduce stellar oscillation and granulation effects
• Limits on Planetary Companions from Doppler Surveys of Nearby Stars
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• A Plateau in the Planet Population Below Twice the Size of Earth
• To Cool is to Accrete: Analytic Scalings for Nebular Accretion of Planetary Atmospheres
• Inside-Out Planet Formation
• Lithium abundances in nearby FGK dwarf and subgiant stars: internal destruction, Galactic chemical evolution, and exoplanets
• Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity
• A new library of theoretical stellar spectra with scaled-solar and alpha-enhanced mixtures
• The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• APF - The Lick Observatory Automated Planet Finder
• A Planet Orbiting the Star Rho Coronae Borealis
• Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars
• SearchCal: a Virtual Observatory tool for searching calibrators in optical long baseline interferometry. I: The bright object case
• Retired A Stars and Their Companions: Eighteen New Jovian Planets
• Interferometric radii of bright Kepler stars with the CHARA Array: θ Cygni and 16 Cygni A and B
• The HARPS-N Rocky Planet Search I. HD219134b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun
• Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars
• Stellar Diameters and Temperatures V. Eleven Newly Characterized Exoplanet Host Stars
• The HARPS search for southern extra-solar planets I. HD330075 b: a new 'hot Jupiter'
• Searching for the signatures of terrestial planets in solar analogs
• The NASA-UC Eta-Earth Program: I. A Super-Earth Orbiting HD 7924
• Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: Nine confirmed planets and two confirmed brown dwarfs
• The NASA-UC Eta-Earth Program: III. A Super-Earth orbiting HD 97658 and a Neptune-mass planet orbiting Gl 785
• Revised Filter Profiles and Zero Points for Broadband Photometry
• Three Super-Earths Orbiting HD 7924
• The NASA-UC Eta-Earth Program: II. A Planet Orbiting HD 156668 with a Minimum Mass of Four Earth Masses
• The Frequency of Low-mass Exoplanets
• Identifying Non-Resonant Kepler Planetary Systems
• The Albedos of Kepler's Close-in super-Earths
• Angular Diameters of the G Subdwarf $\mu$ Cassiopeiae A and the K Dwarfs $\sigma$ Draconis and HR 511 from Interferometric Measurements with the CHARA Array
• Host Star Properties and Transit Exclusion for the HD 38529 Planetary System
• Limits on Stellar Companions to Exoplanet Host Stars With Eccentric Planets
• The Stellar Obliquity and the Long-period planet in the HAT-P-17 Exoplanetary System
• Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

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• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• RadVel: The Radial Velocity Modeling Toolkit
• The Super Earth-Cold Jupiter Relations
• Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
• Far-Ultraviolet Activity Levels of F, G, K, and M dwarf Exoplanet Host Stars
• Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc
• Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets
• Astrophysical Insights into Radial Velocity Jitter from an Analysis of 600 Planet-search Stars
• Radial Velocity Discovery of an Eccentric Jovian World Orbiting at 18 au
• Magnetic and Rotational Evolution of $\rho$ CrB from Asteroseismology with TESS
• Two Planets Straddling the Habitable Zone of The Nearby K Dwarf Gl 414A
• EXPRES IV: Two Additional Planets Orbiting $\rho$ Coronae Borealis Reveal Uncommon System Architecture
• Exclusion of Stellar Companions to Exoplanet Host Stars
• On the 3D secular dynamics of radial-velocity-detected planetary systems
• Confirmation of the Long-Period Planet Orbiting Gliese 411 and the Detection of a New Planet Candidate
• Luminaries in the Sky: The TESS Legacy Sample of Bright Stars. I. Asteroseismic detections in naked-eye main-sequence and sub-giant solar-like oscillators
• The California Legacy Survey II. Occurrence of Giant Planets Beyond the Ice line
• Modeling of two CoRoT solar analogues constrained by seismic and spectroscopic analysis
• The GAPS Programme at TNG -- XXIII. HD 164922 d: a close-in super-Earth discovered with HARPS-N in a system with a long-period Saturn mass companion
• The Missing Link: Testing Galactic Chemical Evolution Models with the First Multi-Isotopic Abundances in Solar Twin Stars
• Earth-like planet predictor: A machine learning approach
• SPORES-HWO. II. Companion Mass Limits and Updated Planet Properties for 120 Future Exoplanet Imaging Targets from 35 yr of Precise Doppler Monitoring
• The California Legacy Survey I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades
• The California Legacy Survey III. On The Shoulders of (Some) Giants: The Relationship between Inner Small Planets and Outer Massive Planets