Study Findings: Detection of Carbon Dioxide and Hydrogen Peroxide on the Stratified Surface of Charon with JWST

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Image (Credit): Charon, Pluto’s largest moon, as captures by NASA’s New Horizons spacecraft. (NASA/JHUAPL/SwRI)

Nature Communications abstract of the study findings:

Charon, Pluto’s largest moon, has been extensively studied, with research focusing on its primitive composition and changes due to radiation and photolysis. However, spectral data have so far been limited to wavelengths below 2.5 μm, leaving key aspects unresolved. Here we present the detection of carbon dioxide (CO2) and hydrogen peroxide (H2O2) on the surface of Charon’s northern hemisphere, using JWST data. These detections add to the known chemical inventory that includes crystalline water ice, ammonia-bearing species, and tholin-like darkening constituents previously revealed by ground- and space-based observations. The H2O2 presence indicates active radiolytic/photolytic processing of the water ice-rich surface by solar ultraviolet and interplanetary medium Lyman-α photons, solar wind, and galactic cosmic rays. Through spectral modeling of the surface, we show that the CO2 is present in pure crystalline form and, possibly, in intimately mixed states on the surface. Endogenically sourced subsurface CO2 exposed on the surface is likely the primary source of this component, with possible contributions from irradiation of hydrocarbons mixed with water ice, interfacial radiolysis between carbon deposits and water ice, and the implantation of energetic carbon ions from the solar wind and solar energetic particles.

Citation: Protopapa, S., Raut, U., Wong, I. et al. Detection of carbon dioxide and hydrogen peroxide on the stratified surface of Charon with JWST. Nat Commun 15, 8247 (2024).
https://doi.org/10.1038/s41467-024-51826-4

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Futurism

Study Finding: Gravitational Instability in a Planet-forming Disk

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Credit: Peter Schmidt from Pixabay

Nature abstract of the study findings:

The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability—if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared with the central star: a disk-to-star mass ratio of 1:10 is widely held as the rough threshold for triggering gravitational instability, inciting substantial non-Keplerian dynamics and generating prominent spiral arms. Although estimating disk masses has historically been challenging, the motion of the gas can reveal the presence of gravitational instability through its effect on the disk-velocity structure. Here we present kinematic evidence of gravitational instability in the disk around AB Aurigae, using deep observations of 13CO and C18O line emission with the Atacama Large Millimeter/submillimeter Array (ALMA). The observed kinematic signals strongly resemble predictions from simulations and analytic modelling. From quantitative comparisons, we infer a disk mass of up to a third of the stellar mass enclosed within 1″ to 5″ on the sky.

Citation: Speedie, J., Dong, R., Hall, C. et al. Gravitational instability in a planet-forming disk. Nature 633, 58–62 (2024).
https://doi.org/10.1038/s41586-024-07877-0

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MIT News

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Space Stories: Oceans on Ariel, Dinosaur-Killer Asteroid from Beyond Jupiter, and the Launch of the Polaris Dawn Mission

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Image (Credit): Uranus and distant galaxies as seen by the James Webb Space Telescope. (NASA, ESA, CSA, STScI)

Here are some recent stories of interest.

—Forbes: “NASA’s Webb Telescope Finds Evidence For An Ocean World Around Uranus“

New observations by the James Webb Space Telescope suggest that an icy moon around Uranus may have an underground liquid ocean. Ariel is one of 27 moons around Uranus, the seventh planet from the sun and the third largest planet in the solar system. It’s one of four moons that scientists have long been interested in as part of a search for water across the solar system, the others being Umbriel, Titania and Oberon.

—Nature: “Dinosaur-killing Chicxulub Asteroid Formed in Solar System’s Outer Reaches“

The object that smashed into Earth and kick-started the extinction that wiped out almost all dinosaurs 66 million years ago was an asteroid that originally formed beyond the orbit of Jupiter, according to geochemical evidence from the impact site in Chicxulub, Mexico. The findings, published on 15 August in Science, suggest that the mass extinction was the result of a train of events that began during the birth of the Solar System. Scientists had long suspected that the Chicxulub impactor, as it is known, was an asteroid from the outer Solar System, and these observations bolster the case.

—Space Daily: “Polaris Dawn Mission Set for August 26 to Advance Commercial Space Exploration“

The Polaris Program, focused on testing and developing new spaceflight technology, is preparing to launch its first mission, Polaris Dawn, aboard SpaceX’s Falcon 9 rocket on Monday, August 26, 2024. This mission marks a significant step forward in commercial space exploration. Key objectives include testing a next-generation spacesuit during the first commercial spacewalk, attempting to achieve the highest altitude for a human spaceflight since the Apollo missions, and evaluating a new communication system through Starlink.

Study Findings: Feasibility of Keeping Mars Warm with Nanoparticles

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Image (Credit): Frost on Olympus Mons (,shaded in blue). (ESA/DLR/FU Berlin)

Science Advances abstract of the study findings:

One-third of Mars’ surface has shallow-buried H2O, but it is currently too cold for use by life. Proposals to warm Mars using greenhouse gases require a large mass of ingredients that are rare on Mars’ surface. However, we show here that artificial aerosols made from materials that are readily available at Mars—for example, conductive nanorods that are ~9 micrometers long—could warm Mars >5 × 103 time smore effectively than the best gases. Such nanoparticles forward-scatter sunlight and efficiently block upwelling thermal infrared. Like the natural dust of Mars, they are swept high into Mars’ atmosphere, allowing delivery from the near-surface. For a 10-year particle lifetime, two climate models indicate that sustained release at 30 liters per second would globally warm Mars by ≳30 kelvin and start to melt the ice. Therefore, if nanoparticles can be made at scale on (or delivered to) Mars, then the barrier to warming of Mars appears to be less high than previously thought.

Citation: Ansari S, Kite ES, Ramirez R, Steele LJ, Mohseni H, Feasibility of keeping Mars warm with nanoparticles, Science Advances, (2024).
10.1126/sciadv.adn4650

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Space.com

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Northwestern University

Space Quote: Vast Water Reserves May Exist Within Martian Crust

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Image (Credit): Martian surface as captured by NASA’s Perseverance Mars rover (NASA/JPL-Caltech/ASU/MSSS)

“These new results demonstrate that liquid water does exist in the Martian subsurface today, not in the form of discrete and isolated lakes, but as liquid water-saturated sediments, or aquifers…On Earth, the subsurface biosphere is truly vast, containing most of the prokaryotic diversity and biomass on our planet. Some investigations even point to an origin of life on Earth precisely deep in the subsurface. Therefore, the astrobiological implications of finally confirming the existence of liquid water habitats kilometers beneath the surface of Mars are truly exciting.”

–Statement by Alberto Fairén, a visiting interdisciplinary planetary scientist and astrobiologist within the department of astronomy at Cornell University, regarding a recent study reporting vast quantities of water may reside between 7 and 12 miles beneath the Martian surface. The study utilized data from NASA’s InSight lander.