Extrasolar giant magnetospheric response to steady-state stellar wind pressure at 10, 5, 1, and 0.2 AU

Abstract

A three-dimensional, multifluid simulation of a giant planet's magnetospheric interaction with steady-state stellar wind from a Sun-like star was performed for four different orbital semi-major axes - 10, 5, 1 and 0.2 AU. We simulate the effect of the increasing, steady-state stellar wind pressure related to the planetary orbital semi-major axis on the global magnetospheric dynamics for a Saturn-like planet, including an Enceladus-like plasma torus. Mass loss processes are shown to vary with orbital distance, with the centrifugal interchange instability displayed only in the 10 AU and 5 AU cases which reach a state of mass loss equilibrium more slowly than the 1 AU or 0.2 AU cases. The compression of the magnetosphere in the 1 AU and 0.2 AU cases contributes to the quenching of the interchange process by increasing the ratio of total plasma thermal energy to corotational energy. The strength of field-aligned currents (FAC), associated with auroral radio emissions, are shown to increase in magnitude and latitudinal coverage with a corresponding shift equatorward from increased dynamic ram pressure experienced in the hotter orbits. Similar to observed hot Jovian planets, the warm exo-Saturn simulated in the current work shows enhanced ion density in the magnetosheath and magnetopause regions, as well as the plasma torus which could contribute to altered transit signals, suggesting that for planets in warmer ($>$0.1 AU) orbits, planetary magnetic field strengths and possibly exomoons - via the plasma torus - could be observable with future missions.

arXiv comment15 pages, 6 figures, accepted by ApJ

References in corpus (20)

• Metals in the Exosphere of the Highly Irradiated Planet WASP-12b
• The On/Off Nature of Star-Planet Interactions
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• Stability of Satellites Around Close-in Extrasolar Giant Planets
• Near-UV Absorption, Chromospheric Activity, and Star-Planet Interactions in the WASP-12 system
• Early UV Ingress in WASP-12b: Measuring Planetary Magnetic Fields
• Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating
• Exomoon habitability constrained by illumination and tidal heating
• Mass Transfer, Transiting Stream and Magnetopause in Close-in Exoplanetary Systems with Applications to WASP-12
• The Dynamics of Stellar Coronae Harboring Hot-jupiters I. A Time-dependent MHD Simulation of the Interplanetary Environment in the HD 189733 Planetary System
• The shocking transit of WASP-12b: Modelling the observed early ingress in the near ultraviolet
• Exoplanet Transit Variability: Bow Shocks and Winds Around HD 189733b
• Hubble Space Telescope observations of the NUV transit of WASP-12b
• Magnetosphere-ionosphere coupling at Jupiter-like exoplanets with internal plasma sources: implications for detectability of auroral radio emissions
• The N2K Consortium VI: Doppler Shifts Without Templates and Three New Short-Period Planets
• The Dynamics of Stellar Coronae Harboring Hot-jupiters II. A Space Weather Event on A Hot-jupiter
• Transit of Exomoon Plasma Tori: New Diagnosis
• A Sensitivity Study of the Enceladus Torus
• Candidates for detecting exoplanetary radio emissions generated by magnetosphere-ionosphere coupling
• Magnetospheres of hot Jupiters: hydrodynamic models & ultraviolet absorption

Cited by in corpus (7)

• The MUSCLES Treasury Survey IV: Scaling Relations for Ultraviolet, Ca II K, and Energetic Particle Fluxes from M Dwarfs
• Magnetised winds and their influence in the escaping upper atmosphere of HD 209458b
• AU Microscopii in the FUV: Observations in Quiescence, During Flares, and Implications for AU Mic b and c
• Effect of stellar wind induced magnetic fields on planetary obstacles of non-magnetized hot Jupiters
• Modeling the Ly$\alpha$ transit absorption of the hot Jupiter HD 189733b
• The Detectability of Radio Auroral Emission from Proxima B
• Inhibition of the electron cyclotron maser instability in the dense magnetosphere of a hot Jupiter