Io’s SO2 and NaCl Wind Fields from ALMA

We present spatially resolved measurements of SO _2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use o...

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Main Authors: Alexander E. Thelen, Katherine de Kleer, Martin A. Cordiner, Imke de Pater, Arielle Moullet, Statia Luszcz-Cook
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal Letters
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Online Access:https://doi.org/10.3847/2041-8213/ad9bb5
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author Alexander E. Thelen
Katherine de Kleer
Martin A. Cordiner
Imke de Pater
Arielle Moullet
Statia Luszcz-Cook
author_facet Alexander E. Thelen
Katherine de Kleer
Martin A. Cordiner
Imke de Pater
Arielle Moullet
Statia Luszcz-Cook
author_sort Alexander E. Thelen
collection DOAJ
description We present spatially resolved measurements of SO _2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use of Doppler shift measurements in emission spectra obtained with the Atacama Large Millimeter/submillimeter Array between ~346 and 430 GHz (~0.70–0.87 mm), line-of-sight winds up to ~−100 m s ^−1 in the approaching direction and >250 m s ^−1 in the receding direction were derived for SO _2 at altitudes of ~10–50 km, while NaCl winds consistently reached ~∣150–200∣ m s ^−1 in localized regions up to ~30 km above the surface. The wind distributions measured at maximum east and west Jovian elongations and on the sub-Jovian hemisphere pre- and posteclipse were found to be significantly different and complex, corroborating the results of simulations that include surface temperature and frost distribution, volcanic activity, and interactions with the Jovian magnetosphere. Further, the wind speeds of SO _2 and NaCl are often inconsistent in direction and magnitude, indicating that the processes that drive the winds for the two molecular species are different and potentially uncoupled; while the SO _2 wind field can be explained through a combination of sublimation-driven winds, plasma torus interactions, and plume activity, the NaCl winds appear to be primarily driven by the plasma torus.
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spelling doaj-art-72e65d4c531644a68dcfee9bba3f15772025-08-20T02:08:47ZengIOP PublishingThe Astrophysical Journal Letters2041-82052024-01-019781L110.3847/2041-8213/ad9bb5Io’s SO2 and NaCl Wind Fields from ALMAAlexander E. Thelen0https://orcid.org/0000-0002-8178-1042Katherine de Kleer1https://orcid.org/0000-0002-9068-3428Martin A. Cordiner2https://orcid.org/0000-0001-8233-2436Imke de Pater3Arielle Moullet4Statia Luszcz-Cook5Division of Geological and Planetary Sciences , California Institute of Technology, Pasadena, CA 91125, USADivision of Geological and Planetary Sciences , California Institute of Technology, Pasadena, CA 91125, USASolar System Exploration Division , NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA; Department of Physics , Catholic University of America, Washington, DC 20064, USADepartment of Astronomy , Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USANational Radio Astronomy Observatory , Charlottesville, VA 22903, USANew York University , New York, NY 10003, USA; American Museum of Natural History , New York, NY 10024, USAWe present spatially resolved measurements of SO _2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use of Doppler shift measurements in emission spectra obtained with the Atacama Large Millimeter/submillimeter Array between ~346 and 430 GHz (~0.70–0.87 mm), line-of-sight winds up to ~−100 m s ^−1 in the approaching direction and >250 m s ^−1 in the receding direction were derived for SO _2 at altitudes of ~10–50 km, while NaCl winds consistently reached ~∣150–200∣ m s ^−1 in localized regions up to ~30 km above the surface. The wind distributions measured at maximum east and west Jovian elongations and on the sub-Jovian hemisphere pre- and posteclipse were found to be significantly different and complex, corroborating the results of simulations that include surface temperature and frost distribution, volcanic activity, and interactions with the Jovian magnetosphere. Further, the wind speeds of SO _2 and NaCl are often inconsistent in direction and magnitude, indicating that the processes that drive the winds for the two molecular species are different and potentially uncoupled; while the SO _2 wind field can be explained through a combination of sublimation-driven winds, plasma torus interactions, and plume activity, the NaCl winds appear to be primarily driven by the plasma torus.https://doi.org/10.3847/2041-8213/ad9bb5IoGalilean satellitesRadio astronomyMillimeter astronomySubmillimeter astronomyAtmospheric dynamics
spellingShingle Alexander E. Thelen
Katherine de Kleer
Martin A. Cordiner
Imke de Pater
Arielle Moullet
Statia Luszcz-Cook
Io’s SO2 and NaCl Wind Fields from ALMA
The Astrophysical Journal Letters
Io
Galilean satellites
Radio astronomy
Millimeter astronomy
Submillimeter astronomy
Atmospheric dynamics
title Io’s SO2 and NaCl Wind Fields from ALMA
title_full Io’s SO2 and NaCl Wind Fields from ALMA
title_fullStr Io’s SO2 and NaCl Wind Fields from ALMA
title_full_unstemmed Io’s SO2 and NaCl Wind Fields from ALMA
title_short Io’s SO2 and NaCl Wind Fields from ALMA
title_sort io s so2 and nacl wind fields from alma
topic Io
Galilean satellites
Radio astronomy
Millimeter astronomy
Submillimeter astronomy
Atmospheric dynamics
url https://doi.org/10.3847/2041-8213/ad9bb5
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