Tidal evolution of exoplanetary systems hosting Potentially Habitable Exoplanets. The cases of LHS-1140 b-c and K2-18 b-c

Abstract

We present a model to study secularly and tidally evolving three-body systems composed by two low-mass planets orbiting a star, in the case where the bodies rotation axes are always perpendicular to the orbital plane. The tidal theory allows us to study the spin and orbit evolution of both stiff Earth-like planets and predominantly gaseous Neptune-like planets. The model is applied to study two recently-discovered exoplanetary systems containing potentially habitable exoplanets (PHE): LHS-1140 b-c and K2-18 b-c. For the former system, we show that both LHS-1140 b and c must be in nearly-circular orbits. For K2-18 b-c, the combined analysis of orbital evolution timescales with the current eccentricity estimation of K2-18 b allows us to conclude that the inner planet (K2-18 c) must be a Neptune-like gaseous body. Only this would allow for the eccentricity of K2-18 b to be in the range of values estimated in recent works ($e=0.20\pm 0.08$), provided that the uniform viscosity coefficient of K2-18 b is greater than $2.4\times 10^{19}\text{Pa s}$ (which is a value characteristic of stiff bodies) and supposing that such system has an age of some Gyr.

arXiv comment9 pages, 6 figures

References in corpus (29)

• Mass-Radius Relationships for Solid Exoplanets
• A New Family of Planets ? "Ocean Planets"
• A temperate rocky super-Earth transiting a nearby cool star
• Ocean Planet or Thick Atmosphere: On the Mass-Radius Relationship for Solid Exoplanets with Massive Atmospheres
• Tidal Locking of Habitable Exoplanets
• Spin-Orbit Evolution Of Short-Period Planets
• Long-term tidal evolution of short-period planets with companions
• Stellar and Planetary Properties of K2 Campaign 1 Candidates and Validation of 17 Planets, Including a Planet Receiving Earth-like Insolation
• Volatile-Rich Earth-Mass Planets in the Habitable Zone
• Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone
• Deformation and tidal evolution of close-in planets and satellites using a Maxwell viscoelastic rheology
• Tidal synchronization of close-in satellites and exoplanets. A rheophysical approach
• A second terrestrial planet orbiting the nearby M dwarf LHS 1140
• Characterization of the K2-18 multi-planetary system with HARPS: A habitable zone super-Earth and discovery of a second, warm super-Earth on a non-coplanar orbit
• Tidal dissipation in rotating low-mass stars and implications for the orbital evolution of close-in planets I. From the PMS to the RGB at solar metallicity
• No pseudosynchronous rotation for terrestrial planets and moons
• Effect of the stellar spin history on the tidal evolution of close-in planets
• Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES
• Interior Structures and Tidal Heating in the TRAPPIST-1 Planets
• Spin-orbit coupling for tidally evolving super-Earths
• Tidal dissipation in rotating low-mass stars and implications for the orbital evolution of close-in massive planets. II. Effect of stellar metallicity
• Tidal synchronization of close-in satellites and exoplanets. II. Spin dynamics and extension to Mercury and exoplanets host stars
• Tidal decay and orbital circularization in close-in two-planet systems
• Exoplanet Characterization by Proxy: a Transiting 2.15 R_Earth Planet Near the Habitable Zone of the Late K dwarf Kepler-61
• Retrieval of the fluid Love number $k_2$ in exoplanetary transit curves
• The Time-Domain Spectroscopic Survey: Target Selection for Repeat Spectroscopy
• Mass-Radius Relationships for Very Low Mass Gaseous Planets
• Tidal synchronization of close-in satellites and exoplanets. III. Tidal dissipation revisited and application to Enceladus
• Rotation and figure evolution in the creep tide theory. A new approach and application to Mercury

Cited by in corpus (5)

• 1D atmospheric study of the temperate sub-Neptune K2-18b
• Hot Rocks Survey III: A deep eclipse for LHS 1140c and a new Gaussian process method to account for correlated noise in individual pixels
• Potential Interior Structures and Habitability of Super-Earth Exoplanets LHS 1140 b, K2-18 b, TOI-1452 b and TOI-1468 c
• A reanalysis of the LHS 1140 b atmosphere observed with the Hubble Space Telescope
• On Tides and Exoplanets