EXTRASOLAR GIANT MAGNETOSPHERIC RESPONSE TO STEADY-STATE STELLAR WIND PRESSURE AT 10, 5, 1, AND 0.2 au

Journal Article · Wed Aug 10 00:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/827/1/77· OSTI ID:22679527

Tilley, Matt A.; Harnett, Erika M.; Winglee, Robert M. ^[1]

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1. Department of Earth and Space Sciences, University of Washington, Johnson Hall, Box 351310, Seattle, WA 98195 (United States)

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 semimajor 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 semimajor 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 and 5 au cases, which reach a state of mass-loss equilibrium more slowly than the 1 or 0.2 au cases. The compression of the magnetosphere in the 1 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, associated with auroral radio emissions, is 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.

• OSTI ID: 22679527
• Journal Information: Astrophysical Journal, Vol. 827, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COMPRESSION
DETECTION
DISTANCE
EMISSION
FLUTE INSTABILITY
INTERACTIONS
ION DENSITY
IONS
MAGNETIC FIELDS
MAGNETOPAUSE
MAGNETOSHEATH
MASS TRANSFER
ORBITS
PLASMA
SATELLITES
SATURN PLANET
SIMULATION
STEADY-STATE CONDITIONS
STELLAR WINDS
THREE-DIMENSIONAL CALCULATIONS