Exomoons in Systems with a Strong Perturber: Applications to $\alpha$ Cen AB

Abstract

The presence of a stellar companion can place constraints on occurrence and orbital evolution of satellites orbiting exoplanets, i.e., exomoons. In this work we revise earlier orbital stability limits for retrograde orbits in the case of a three body system consisting of star-planet-satellite. The latter reads $a_{\mathrm{sat}}^{\mathrm{crit}}\approx 0.668(1-1.236e_{\mathrm{p}})$ for $e_p\le 0.8$ in units of the Hill Radius and represents the lower critical orbit as a function of the planetary eccentricity $e_{\mathrm{p}}$. A similar formula is determined for exomoons hosted by planets in binary star systems, where $e_{\mathrm{p}}$ is replaced with the components of free and forced eccentricity from secular orbit evolution theory. By exploring the dynamics of putative exomoons in $\alpha$ Centauri AB we find that the outer stability limit can be much less than half the Hill Radius due to oscillations in the planetary orbital eccentricity caused by the gravitational interaction with the binary star. We show, furthermore, how the resulting truncation of the outer stability limit can affect the outward tidal migration and potential observability of exomoons through transit timing variations (TTVs). Typical TTV (RMS) amplitudes induced by exomoons in binary systems are $\lesssim$10 min and appear more likely for planets orbiting the less massive stellar component. A GitHub repository (saturnaxis/exomoon-in-binaries) is available to reproduce figures.

arXiv comment16 pages, 11 figures, 3 tables; accepted in Astronomical Journal; for the GitHub repository, see https://github.com/saturnaxis/exomoon-in-binaries

References in corpus (98)

• Array Programming with NumPy
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• REBOUND: An open-source multi-purpose N-body code for collisional dynamics
• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• On detecting terrestrial planets with timing of giant planet transits
• Kepler-16: A Transiting Circumbinary Planet
• IAS15: A fast, adaptive, high-order integrator for gravitational dynamics, accurate to machine precision over a billion orbits
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Kepler-47: A Transiting Circumbinary Multi-Planet System
• Is tidal heating sufficient to explain bloated exoplanets? Consistent calculations accounting for finite initial eccentricity
• A Planetary Companion to gamma Cephei A
• Transit timing effects due to an exomoon
• REBOUNDx: A Library for Adding Conservative and Dissipative Forces to Otherwise Symplectic N-body Integrations
• Stability of Satellites Around Close-in Extrasolar Giant Planets
• Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System
• The Neptune-Sized Circumbinary Planet Kepler-38b
• Transit timing effects due to an exomoon II
• The Hunt for Exomoons with Kepler (HEK): I. Description of a New Observational Project
• Resonance locking in giant planets indicated by the rapid orbital expansion of Titan
• Irregular Satellites of the Planets: Products of Capture in the Early Solar System
• Terrestrial Planet Formation Around Individual Stars Within Binary Star Systems
• Constraining the difference in convective blueshift between the components of alpha Cen with precise radial velocities
• Kepler-1647b: the largest and longest-period Kepler transiting circumbinary planet
• Transit Timing Observations from Kepler: I. Statistical Analysis of the First Four Months
• A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the two transiting planets in the Kepler-47 System
• Resonance Overlap is Responsible for Ejecting Planets in Binary Systems
• The Hunt for Exomoons with Kepler (HEK): II. Analysis of Seven Viable Satellite-Hosting Planet Candidates
• Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M Dwarf System at 6.9 Parsecs
• TOI-1338: TESS' First Transiting Circumbinary Planet
• The Hunt for Exomoons with Kepler (HEK): V. A Survey of 41 Planetary Candidates for Exomoons
• Detecting companions to extrasolar planets using mutual events
• Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System
• Against all odds? Forming the planet of the HD196885 binary
• The Hunt for Exomoons with Kepler (HEK): IV. A Search for Moons around Eight M-Dwarfs
• Stability of prograde and retrograde planets in circular binary systems
• The ELODIE survey for northern extra-solar planets IV. HD196885, a close binary star with a 3.7-year planet
• Outcomes and Duration of Tidal Evolution in a Star-Planet-Moon System
• Mercury-T: A new code to study tidally evolving multi-planet systems. Applications to Kepler-62
• The Hunt for Exomoons with Kepler (HEK): III. The First Search for an Exomoon around a Habitable-Zone Planet
• New prospects for observing and cataloguing exoplanets in well detached binaries
• Dynamical Stability of Earth-Like Planetary Orbits in Binary Systems
• Habitable Planet Formation in Binary-Planetary Systems
• New developments for modern celestial mechanics. I. General coplanar three-body systems. Application to exoplanets
• A Gas-poor Planetesimal Capture Model for the Formation of Giant Planet Satellite Systems
• Detecting extrasolar moons akin to solar system satellites with an orbital sampling effect
• On the detection of Exomoons: A search in Kepler data for the orbital sampling effect and the scatter peak
• Detection of Exomoons Through Observation of Radio Emissions
• The Center of Light: Spectroastrometric Detection of Exomoons
• Signals of exomoons in averaged light curves of exoplanets
• The fate of moons of close-in giant exoplanets
• The Planet Host Star Gamma Cephei: Physical Properties, the Binary Orbit, and the Mass of the Substellar Companion
• A semi-empirical stability criterion for real planetary systems
• Habitability of Earth-type Planets and Moons in the Kepler-16 System
• Long-Term Stability of Planets in the $\alpha$ Centauri System
• Resonant Removal of Exomoons During Planetary Migration
• Orbital Stability of Circumstellar Planets in Binary Systems
• Parallax and masses of alpha Centauri revisited
• Imaging low-mass planets within the habitable zone of α Centauri
• Stability of Satellites in Closely Packed Planetary Systems
• Hubble Space Telescope search for the transit of the Earth-mass exoplanet Alpha Centauri Bb
• Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing Binary
• Five planets and an independent confirmation of HD 196885Ab from Lick Observatory
• Chaotic dynamics of the planet in HD 196885 AB
• Chaotic quadruple secular evolution and the production of misaligned exomoons and Warm Jupiters in stellar multiples
• Detecting Exomoons Via Doppler Monitoring of Directly Imaged Exoplanets
• Unravelling tidal dissipation in gaseous giant planets
• Eccentricity evolution in hierarchical triple systems with eccentric outer binaries
• Planet Detectability in the Alpha Centauri System
• Secular dynamics of planetesimals in tight binary systems: Application to Gamma-Cephei
• Techniques for High-Contrast Imaging in Multi-Star Systems II: Multi-Star Wavefront Control
• The effect of close-in giant planets' evolution on tidal-induced migration of exomoons
• Orbital Stability of Exomoons and Submoons with Applications to Kepler 1625b-I
• Ploonets: formation, evolution and detectability of tidally detached exomoons
• On the radio detection of multiple-exomoon systems due to plasma torus sharing
• Long-Term Stability of Tightly Packed Multi-Planet Systems in Prograde, Coplanar, Circumstellar Orbits within the $\alpha$ Centauri AB System
• Application of chaos indicators in the study of dynamics of S-type extrasolar planets in stellar binaries
• The Exomoon Corridor: Half of all exomoons exhibit TTV frequencies within a narrow window due to aliasing
• Exoplanets Torqued by the Combined Tides of a Moon and Parent Star
• Catching a planet: A tidal capture origin for the exomoon candidate Kepler 1625b I
• Modeling the Orbital Sampling Effect of Extrasolar Moons
• The Mt John University Observatory Search For Earth-mass Planets In The Habitable Zone Of Alpha Centauri
• Stability of exomoons around the Kepler transiting circumbinary planets
• Dynamical analysis and constraints for the HD 196885 system
• Application of Orbital Stability and Tidal Migration Constraints for Exomoon Candidates
• The Possible Moon of Kepler-90g is a False Positive
• Secular Orbit Evolution in Systems with a Strong External Perturber - A Simple and Accurate Model
• Searching for Planets Orbiting Alpha Centauri A with the James Webb Space Telescope
• Long-Term Stability of Planets in the $\alpha$ Centauri System, II: Forced Eccentricities
• The ominous fate of exomoons around hot Jupiters in the high-eccentricity migration scenario
• Impossible moons -- Transit timing effects that cannot be due to an exomoon
• Obliquity Evolution of Circumstellar Planets in Sun-like Stellar Binaries
• Searching for Earth-mass planets around $\alpha$ Centauri: precise radial velocities from contaminated spectra
• Space telescope design to directly image the habitable zone of Alpha Centauri
• Detecting Exoplanets Using Eclipsing Binaries as Natural Starshades
• A method to directly image exoplanets in multi-star systems such as Alpha-Centauri

Cited by in corpus (6)

• Cronomoons: origin, dynamics, and light-curve features of ringed exomoons
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• Extreme exomoons in WASP-49 Ab: dynamics and detectability
• Updated Studies on Exomoons in the HD 23079 System
• Transit Duration and Timing Variations from Binary Planets
• Moon-packing around an Earth-mass Planet