Orbital Architectures of Planet-Hosting Binaries: I. Forming Five Small Planets in the Truncated Disk of Kepler-444A

Abstract

We present the first results from our Keck program investigating the orbital architectures of planet-hosting multiple star systems. Kepler-444 is a metal-poor triple star system that hosts five sub-Earth-sized planets orbiting the primary star (Kepler-444A), as well as a spatially unresolved pair of M dwarfs (Kepler-444BC) at a projected distance of 1.8" (66 AU). We combine our Keck/NIRC2 adaptive optics astrometry with multi-epoch Keck/HIRES RVs of all three stars to determine a precise orbit for the BC pair around A, given their empirically constrained masses. We measure minimal astrometric motion ($1.0\pm 0.6$ mas yr${}^{-1}$, or $0.17\pm 0.10$ km s${}^{-1}$), but our RVs reveal significant orbital velocity ($1.7\pm 0.2$ km s${}^{-1}$) and acceleration ($7.8\pm 0.5$ m s${}^{-1}$ yr${}^{-1}$). We determine a highly eccentric stellar orbit ($e=0.864\pm 0.023$) that brings the tight M dwarf pair within $5.0_{-1.0}^{+0.9}$ AU of the planetary system. We validate that the system is dynamically stable in its present configuration via n-body simulations. We find that the A$-$BC orbit and planetary orbits are likely aligned (98%) given that they both have edge-on orbits and misalignment induces precession of the planets out of transit. We conclude that the stars were likely on their current orbits during the epoch of planet formation, truncating the protoplanetary disk at $\approx$2 AU. This truncated disk would have been severely depleted of solid material from which to form the total $\approx$1.5 $M_{\mathrm{Earth}}$ of planets. We thereby strongly constrain the efficiency of the conversion of dust into planets and suggest that the Kepler-444 system is consistent with models that explain the formation of more typical close-in Kepler planets in normal, not truncated, disks.

accepted to ApJ

References in corpus (16)

• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• An ancient extrasolar system with five sub-Earth-size planets
• Global Models for the Evolution of Embedded, Accreting Protostellar Disks
• Formation of close in Super-Earths \& Mini-Neptunes: Required Disk Masses \& Their Implications
• Influence of Stellar Multiplicity On Planet Formation. II. Planets Are Less Common in Multiple-Star Systems with Separations Smaller than 1500 AU
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• The Mass Budget of Planet Forming Discs: Isolating the Epoch of Planetesimal Formation
• High-resolution Multi-band Imaging for Validation and Characterization of Small Kepler Planets
• New Evidence for a Substellar Luminosity Problem: Dynamical Mass for the Brown Dwarf Binary Gl 417BC
• Disk Truncation and Planet Formation in gamma Cephei
• Protoplanetary Disk Masses in the Young NGC 2024 Cluster
• Viscosity prescription for gravitationally unstable accretion disks
• Variable Accretion Processes in the Young Binary-Star System UY Aur

Cited by in corpus (57)

• Imaging Extrasolar Giant Planets
• How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_{\odot }$
• The Impact of Stellar Multiplicity on Planetary Systems, I.: The Ruinous Influence of Close Binary Companions
• Individual Dynamical Masses of Ultracool Dwarfs
• The Updated Multiple Star Catalog
• TESS Hunt for Young and Maturing Exoplanets (THYME): A planet in the 45 Myr Tucana-Horologium association
• Impact of Binary Stars on Planet Statistics -- I. Planet Occurrence Rates, Trends with Stellar Mass, and Wide Companions to Hot Jupiter Hosts
• Orbits for the Impatient: A Bayesian Rejection Sampling Method for Quickly Fitting the Orbits of Long-Period Exoplanets
• Direct Imaging Discovery of a Jovian Exoplanet Within a Triple Star System
• Hiding Planets Behind a Big Friend: Mutual Inclinations of Multi-Planet Systems with External Companions
• Dawes Review. The tidal downsizing hypothesis of planet formation
• Orbit and Dynamical Mass of the Late-T Dwarf Gl 758 B
• The Kepler Giant Planet Search. I: A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory
• Adaptive Optics imaging of VHS 1256-1257: A Low Mass Companion to a Brown Dwarf Binary System
• Speckle Observations of TESS Exoplanet Host Stars: Understanding the Binary Exoplanet Host Star Orbital Period Distribution
• The TESS-Keck Survey II: An Ultra-Short Period Rocky Planet and its Siblings Transiting the Galactic Thick-Disk Star TOI-561
• WISE J072003.20-084651.2B Is A Massive T Dwarf
• Orbital Architectures of Planet-Hosting Binaries II. Low Mutual Inclinations Between Planetary and Stellar Orbits
• Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of Gaia
• The Kepler Peas in a Pod Pattern is Astrophysical
• The effect of radiative feedback on disc fragmentation
• High-Precision Radio and Infrared Astrometry of LSPM J1314+1320AB - II: Testing Pre--Main-Sequence Models at the Lithium Depletion Boundary with Dynamical Masses
• The Hawaii Infrared Parallax Program. III. 2MASS J0249-0557 c: A Wide Planetary-mass Companion to a Low-mass Binary in the beta Pic Moving Group
• Eccentric Companions to Kepler-448b and Kepler-693b: Clues to the Formation of Warm Jupiters
• Strong HI Lyman-$\alpha$ variations from the 11 Gyr-old host star Kepler-444: a planetary origin ?
• The Effect of Binarity on Circumstellar Disk Evolution
• Mass, Density, and Formation Constraints in the Compact, Sub-Earth Kepler-444 System including Two Mars-Mass Planets
• Peculiar architectures for the WASP-53 and WASP-81 planet-hosting systems
• Formation of S-type planets in close binaries: scattering induced tidal capture of circumbinary planets
• Detecting Unresolved Binaries in TESS Data with Speckle Imaging
• An ALMA Survey of faint disks in the Chamaeleon I star-forming region: Why are some Class II disks so faint?
• Planetary system around LTT 1445A unveiled by ESPRESSO: Multiple planets in a triple M-dwarf system
• 3.8um Imaging of 400-600K Brown Dwarfs and Orbital Constraints for WISEP J045853.90+643452.6AB
• K2-288Bb: A Small Temperate Planet in a Low-mass Binary System Discovered by Citizen Scientists
• A Dwarf Protoplanetary Disk around XZ Tau B
• Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. I. Confirmation of an Eccentric, Cool Jupiter With an Interior Earth-sized Planet Orbiting Kepler-1514
• Long-lived protoplanetary disks in multiple systems: the VLA view of HD 98800
• Constraining the orbit of the planet-hosting binary $\tau$ Boötis: Clues about planetary formation and migration
• Revisiting Kepler-444. II. Rotational, orbital and high-energy fluxes evolution of the system
• Lyman-$\alpha$ Observations of High Radial Velocity Low-Mass Stars Ross 1044 and Ross 825
• Synergies between Asteroseismology and Exoplanetary Science
• The long-term dynamical evolution of disc-fragmented multiple systems in the Solar Neighborhood
• Disks in close binary stars: γ-Cephei revisited
• The McDonald Accelerating Stars Survey (MASS): Architecture of the Ancient Five-Planet Host System Kepler-444
• An Early Catalog of Planet Hosting Multiple Star Systems of Order Three and Higher
• Obliquity Evolution of Circumstellar Planets in Sun-like Stellar Binaries
• Dynamical masses for the Pleiades binary system HII-2147
• Robo-AO Kepler Asteroseismic Survey. I. Adaptive optics imaging of 99 asteroseismic Kepler dwarfs and subgiants
• Dynamical Architectures of S-type Transiting Planets in Binaries I: Target Selection using Hipparcos and Gaia proper motion anomalies
• Effects of a Binary Companion Star on Habitability of Tidally Locked Planets around an M-type Host Star
• Boyajian's Star B: The co-moving stellar companion to KIC 8462852
• Global dynamics and architecture of the Kepler-444 system
• An Incipient Debris Disk in the Chamaeleon I Cloud
• Revisiting Kepler-444 Part I. Seismic modelling and inversions of stellar structure
• Dynamical Architectures of S-type Transiting Planets in Binaries II: A Dichotomy in Orbital Alignment of Small Planets in Close Binary Systems
• Three-Body Problem in Modified Dynamics
• Higher-Order Mean-Motion Resonances Can Form in Type-I Disk Migration