Sharper Than Ever – Io’s Volcanic Surfaces Revealed by New Telescope Technology

Jupiter’s moon Io, imaged by SHARK-VIS on January 10, 2024. This is the highest-resolution image of Io ever taken by an Earth-based telescope. The image combines three spectral bands—infrared, red, and yellow—to highlight the reddish ring around Pele volcano (below and to the right of the moon’s center) and the white ring around Pillan Patera, to the right of Pele. Credit: INAF/Large Binocular Telescope Observatory/Georgia State University; IRV band observations from SHARK-VIS/F. Pedicure; editing by D. Hope, S. Jefferies, G. Li Causi

Astronomers have caught a volcanic event in JupiterMoon Io at a resolution never before achieved with Earth-based observations, advancing our understanding of volcanic processes throughout the Solar System.

New images of Jupiter’s volcano-filled moon Io, taken by the Large Binocular Telescope on Mount Graham in Arizona, provide the highest resolution of Io ever achieved by an Earth-based instrument. The observations were made possible by a new high-contrast optical imaging instrument, called SHARK-VIS, and the telescope’s adaptive optics system, which compensates for blur caused by atmospheric turbulence.

Unprecedented details are revealed

The images will be published in the magazine Geophysical Research Letters, reveal surface features up to 50 miles across, a spatial resolution previously only possible with spacecraft sent to Jupiter. That’s the equivalent of taking a picture of an object 100 miles across, according to the research team.

SHARK-VIS allowed researchers to identify a major resurgence event around Pele, one of Io’s most prominent volcanoes. According to the paper’s first author, Al Conrad, the eruptions on Io, the most active volcanic body in the solar system, dwarf their contemporaries on Earth.

Interferometer of the large binocular telescope

The Large Binocular Telescope Interferometer, or LBTI, is a ground-based instrument that connects two 8-meter-class telescopes on Mount Graham in Arizona to form the world’s largest single-mount telescope. The interferometer is designed to detect and study stars and planets outside our solar system. Credits: NASA/JPL-Caltech

Volcanic views from Io

“Io therefore presents a unique opportunity to learn about the powerful explosions that helped shape the surfaces of Earth and the Moon in their distant past,” said Conrad, staff scientist at the Large Binocular Telescope Observatory. The Large Binocular Telescope, or LBT, is part of the Mount Graham International Observatory, a division of the University of Arizona’s Steward Observatory.

Conrad added that studies like this will help researchers understand why some worlds in the solar system are volcanic but not others. They may also one day shed light on volcanic worlds in the exoplanets systems around nearby stars.

Gravitational dynamics and volcanism

Slightly larger than Earth’s moon, Io is the innermost Galilean moon of Jupiter, which in addition to Io includes Europa, Ganymede and Callisto. Locked in a gravitational “tug of war” between Jupiter, Europa and Ganymede, Io is constantly being squeezed, leading to frictional heat building up in its interior – believed to be the cause of its persistent and widespread activity volcanic.

By monitoring eruptions on Io’s surface, scientists hope to gain insights into the movement of heat-driven material beneath the moon’s surface, its internal structure, and ultimately, the tidal heating mechanism responsible for the moon’s intense volcanism. Io’s.

Cross-section through the crust of Io

A cross section through Io’s crust depicting scientists’ current understanding of the geological and chemical processes that sculpt the surface and produce the moon’s atmosphere. To the left is a red sulfur plume and ring similar to that created by the Pele lava lake. Faults in the mostly cold lithosphere act as pathways for sulfur-rich silicate magma to reach the surface. Io’s interior is heated by friction caused by gravitational pulls from Jupiter and two of its moons, Europa and Ganymede, which generate molten magma. Credit: de Pater et al., 2021, Annual Reviews, based on a figure by Doug Beckner, James Tuttle Keane, Ashley Davies

Historical context and recent discoveries

Io’s volcanic activity was first discovered in 1979, when Linda Morabito, an engineer at NASAThe Voyager mission spotted an explosion plume in one of the images taken by the spacecraft during its famous “Grand Tour” of the outer planets. Since then, countless observations have been made documenting the restless nature of Io, both from space and from Earth-based telescopes.

Study co-author Ashley Davies, a principal scientist at NASA’s Jet Propulsion Laboratory (JPL), said the new image obtained by SHARK-VIS is so rich in detail that it has allowed the team to identify a major resurgence event in which the plume is deposited around a prominent volcano known as Pele, located in the hemisphere south of Io near the equator. , is being covered by eruption deposits from Pillan Patera, a neighboring volcano. A similar burst sequence was observed by NASA’s Galileo spacecraft, which explored the Jupiter system between 1995 and 2003.

Technological advances in ground-based observations

“We interpret the changes as dark lava deposits and white sulfur dioxide deposits from an eruption at Pillan Patera, which partially cover the red, sulphur-rich plume deposit of Pele,” said Davies. “Before SHARK-VIS, such reappearance events were impossible to observe from Earth.”

While the telescope’s infrared images can detect hot spots caused by ongoing volcanic eruptions, they are not sharp enough to reveal surface details and clearly identify the locations of eruptions, explained co-author Imke de Pater, professor emeritus of astronomy at the University of California – Berkeley.

“Sharper images in visible wavelengths such as those provided by SHARK-VIS and LBT are essential to identify both the locations of eruptions and surface changes not discernible in the infrared, such as new plume deposits,” de Pater said, adding that visible light observations provide researchers with with vital context for interpreting infrared observations, including those from spacecraft such as Juno, which is currently orbiting Jupiter.

Technological advances in observational astronomy

SHARK-VIS was built by the Italian National Institute for Astrophysics at the Astronomical Observatory of Rome and is managed by a team led by principal investigator Fernando Pedichini, assisted by project manager Roberto Piazzesi. In 2023, it was installed, along with its complementary near-infrared instrument SHARK-NIR, on the LBT to take full advantage of the telescope’s outstanding adaptive optics system. The instrument houses a fast, low-noise camera that allows it to survey the sky in “quick imaging” mode, capturing slow-motion images that freeze optical distortions caused by atmospheric turbulence, and process the data in a unprecedented level. sharpness.

Gianluca Li Causi, data processing manager for SHARK-VIS at the Italian National Institute for Astrophysics, explained how it works: “We process our data on the computer to remove any trace of the sensor’s electronic footprint. We then select the best frameworks and combine them using a very efficient software package called Kraken, developed by our colleagues Douglas Hope and Stuart Jefferies from Georgia State University. Kraken allows us to remove atmospheric effects, revealing Io with incredible sharpness.”

Future perspectives in solar system observation

SHARK-VIS instrument scientist Simone Antoniucci said he anticipates making new observations of objects throughout the solar system.

“Shark-VIS’s sharp vision is particularly suitable for observing the surfaces of many solar system bodies, not only the moons of the giant planets, but also asteroids,” he said. “We’ve already observed some of them, with the data currently being analyzed, and we’re planning to observe more.”

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