SearcharxivSearch

arXiv · 2312.10651

Gas Giant Simulations of Eddy-Driven Jets Accompanied by Deep Meridional Circulation

Abstract

Jupiter's atmosphere comprises several dynamical regimes: the equatorial eastward flows and surrounding retrograde jets; the midlatitudes, with the eddy-driven, alternating jet-streams and meridional circulation cells; and the jet-free turbulent polar region. Despite intensive research conducted on each of these dynamical regimes over the past decades, they remain only partially understood. Saturn's atmosphere also encompasses similar distinguishable regimes, but observational evidence for midlatitude deep meridional cells is lacking. Models offer a variety of explanations for each of these regions, but only a few are capable of simulating more than one of the regimes at once. This study presents new numerical simulations using a 3D deep anelastic model that can reproduce the equatorial flows as well as the midlatitudinal pattern of the mostly barotropic, alternating eddy-driven jets and the meridional circulation cells accompanying them. These simulations are consistent with recent Juno mission gravity and microwave data. We find that the vertical eddy momentum fluxes are as important as the meridional eddy momentum fluxes, which drive the midlatitudinal circulation on Earth. In addition, we discuss the parameters controlling the number of midlatitudinal jets/cells, their extent, strength, and location. We identify the strong relationship between meridional circulation and the zonal jets in a deep convection setup, and analyze the mechanism responsible for their generation and maintenance. The analysis presented here provides another step in the ongoing pursuit of understanding the deep atmospheres of gas giants.

Explore related subjects

Keep this discovery

BibTeXRIS

Keren Duer, Eli Galanti, Yohai Kaspi. 2023-12-17. Gas Giant Simulations of Eddy-Driven Jets Accompanied by Deep Meridional Circulation. https://doi.org/10.1029/2023av000908

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Planetary Accretion Is Less Frequent in Wide Binaries: Evidence from Metal-Enriched White Dwarfs in DESI DR1

Binary stars are common in the Galaxy, and understanding how stellar binarity influences the formation and evolution of planetary systems is an active area of research. In this study, we use metal-enriched white dwarfs in wide binaries as tracers of long-lived planetary systems. With Data Release 1 from the Dark Energy Spectroscopic Instrument (DESI), we find that the fraction of cool metal-enriched white dwarfs in wide binaries is 9.8\,$\pm$\,2.1\%, significantly lower (4.7\,$\sigma$) than the 20.5\,$\pm$\,0.9\% in a control sample of single systems. Furthermore, we identify a tentative dependence of metal enrichment on projected separation and white dwarf effective temperature, where enrichment fraction decreases at smaller separations and lower temperatures. These findings indicate that, compared to single stars, binary systems either start with smaller initial planetary reservoirs due to suppressed planetesimal formation or undergo more rapid depletion of planetary material during the initial part of the white dwarf stage.

astro-ph.EP

The Mysterious Inspiral of WASP-12b: Why Obliquity Tides Cannot Drive Orbital Decay

WASP-12b's orbit is decaying, for unknown reasons. The planet's period is shrinking more rapidly than can be attributed to equilibrium tides or dynamical tides in a main-sequence star. Planetary obliquity tides could be sufficiently dissipative to drive WASP-12b's inspiral, but would also damp the planet's obliquity, halting the decay. Millholland & Laughlin proposed that a nearby, low-mass planet ($\sim 10$ M$_\oplus$) is maintaining a large obliquity for WASP-12b, sustaining the dissipation. We re-evaluated this hypothesis, finding that the companion must be more massive than originally proposed ($\gtrsim 65$ M$_\oplus$) to absorb WASP-12b's orbital angular momentum. Radial velocity data allowed us to rule out a companion of this type. Any companions within $3$ AU have $K \lesssim 14$ m/s at $95$% confidence.

astro-ph.EP

Lava Tube Exploration with LunarLeaper

Lunar pits, some of which are interpreted as collapse features into underlying lava tubes, expose otherwise inaccessible stratigraphy and may provide entry points to subsurface voids that preserve records of lunar volcanism and offer potential sites for future human exploration. We synthesize the current state of knowledge on lunar pits and lava tubes, covering their morphological characteristics, classification, proposed formation mechanisms, mechanical stability, and detection from orbit. We then review the open science questions that pit and pit-wall investigation is uniquely placed to address, spanning the volcanic stratigraphy of the lunar maria, the structure and lateral variability of the regolith, and the dimensions and accessibility of subsurface conduits. To evaluate how these questions can be tackled in situ, we assess the feasibility and expected performance of geophysical and remote-sensing investigations for subsurface voids and surface exposures, mainly focusing on gravity measurements, ground-penetrating radar, high-resolution imaging, and spectroscopy. Building on this, we present LunarLeaper, a small legged robot mission concept combining a gravimeter, ground-penetrating radar, high-resolution imager, spectrometer, and leg-based geomechanical experiments to deliver the first in situ investigation of a mare pit. The concept targets the Marius Hills Pit and its associated rille, with a mobility architecture optimized for the rugged terrain encountered at pit edges and funnel slopes.

astro-ph.EP