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| Open AccessIron alloys of volatile elements in the deep Earth’s interior
Many volatile elements are depleted in the bulk silicate Earth. Here, the authors found that these volatile elements tend to react with Fe under pressure and may be sequestered within Earth’s core by forming substitutional Fe alloys.
- Yifan Tian
- , Peiyu Zhang
- & Hanyu Liu
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Article
| Open AccessExtending carbon chemistry at high-pressure by synthesis of CaC2 and Ca3C7 with deprotonated polyacene- and para-poly(indenoindene)-like nanoribbons
The authors demonstrate that carbides with infinite chains of fused [C6] and [C5] rings are synthesized at deep planetary pressures and temperatures. Hydrolysis of these carbides may lead to polycyclic aromatic hydrocarbons in the Universe.
- Saiana Khandarkhaeva
- , Timofey Fedotenko
- & Leonid Dubrovinsky
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| Open AccessFar-travelled 3700 km lateral magma propagation just below the surface of Venus
In this study, the authors trace lateral magma movement in a ~ 3700 km long fracture on Venus. This Great Dyke of Atla Regio is the longest so-far traced on Venus (and in the solar system) and belongs to a giant radiating dyke swarm of the Ozza Mons volcano of the Atla Regio plume.
- H. El Bilali
- & R. E. Ernst
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Article
| Open AccessThe second Venus flyby of BepiColombo mission reveals stable atmosphere over decades
On its way to Mercury, BepiColombo spacecraft made two flybys of Venus. Here, the authors show spectrally resolved measurements of Venus’ atmosphere during BepiColombo’s second flyby and reveal that Venusian atmosphere has been stable since 1980s.
- Jörn Helbert
- , Rainer Haus
- & Harald Hiesinger
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| Open AccessDirect detection of atomic oxygen on the dayside and nightside of Venus
Atomic oxygen is important for the photochemistry and energy balance of Venus’s atmosphere, but it was not directly observed on the dayside of Venus. Here, the authors show direct detection of atomic oxygen on the both dayside and nightside of Venus by measuring its ground-state transition at 4.74 THz.
- Heinz-Wilhelm Hübers
- , Heiko Richter
- & Helmut Wiesemeyer
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Article
| Open AccessDetection of magnetospheric ion drift patterns at Mars
Mars lacks a global intrinsic magnetic field. Here, the authors show wedge-like dispersion structures of Hydrogen ions exhibiting butterfly-shaped distributions, which was previously found only in intrinsic magnetospheres.
- Chi Zhang
- , Hans Nilsson
- & Stas Barabash
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Article
| Open AccessRapid transition from primary to secondary crust building on the Moon explained by mantle overturn
Overturn of late stage lunar magma ocean cumulates triggers a rapid & short-lived episode of lower mantle melting that explains the key volume, geochronological, & spatial characteristics of the earliest secondary crust on the Moon (Mg-suite).
- Tabb C. Prissel
- , Nan Zhang
- & Haoyuan Li
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| Open AccessDirect evidence of substorm-related impulsive injections of electrons at Mercury
BepiColombo mission had its first Mercury flyby on 1 October 2021. Here, the authors show plasma measurements taken during this flyby, which reveals that electron injections and subsequent energy-dependent drift is a universal mechanism generating aurorae in the planetary magnetospheres.
- Sae Aizawa
- , Yuki Harada
- & Go Murakami
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Article
| Open AccessEvidence for structural control of mare volcanism in lunar compressional tectonic settings
On the Moon, evidence has been found for the preexisting fault reactivation origin (tectonic inversion) of contractional wrinkle ridges in mare basins and the consequent structural control of volcanic eruptions in compressional tectonic settings.
- Feng Zhang
- , Alberto Pizzi
- & Yongliao Zou
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Article
| Open AccessUntrackable distal ejecta on planetary surfaces
Heterogeneous shock impedances of planetary materials cause abrupt changes of ejection angles, forming non-radial ejecta. Interpretations for provenances of surface deposits and ages derived from crater counts are affected by such untrackable ejecta.
- Rui Xu
- , Zhiyong Xiao
- & Jun Cui
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Article
| Open AccessThe sound of a Martian dust devil
Dust devils are common on Mars and understanding their dynamics is important to gain insights about the meteorology of the planet. Here, the authors show characteristics of a Martian dust devil and its sound from Perseverance rover multi-sensor data combined with modelling.
- N. Murdoch
- , A. E. Stott
- & D. Mimoun
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| Open AccessA changing thermal regime revealed from shallow to deep basalt source melting in the Moon
Ancient (~3.9 Ga) KREEP-free basalts were sourced from a relatively cool and shallow pyroxene-rich mantle distinct from later-erupted (<3.8 Ga) KREEP-bearing basalts, indicating a fundamental change in melting regimes in the Moon.
- Yash Srivastava
- , Amit Basu Sarbadhikari
- & Atsushi Takenouchi
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| Open AccessInner southern magnetosphere observation of Mercury via SERENA ion sensors in BepiColombo mission
BepiColombo mission had already two flybys of Mercury, over the total of six, as planned before entering the planet’s orbit in 2025. Here, the authors show the first ion measurements of Mercury’s inner southern magnetosphere during BepiColombo mission’s first Mercury flyby.
- S. Orsini
- , A. Milillo
- & A. Vorburger
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| Open AccessUsing MARSIS signal attenuation to assess the presence of South Polar Layered Deposit subglacial brines
MARSIS attenuation and thermal data confirm that liquid brines are the most plausible source for the bright reflections at the base of the South Polar Layered Deposits. Such results also justify why SHARAD does not penetrate to the base of the ice.
- Sebastian E. Lauro
- , Elena Pettinelli
- & Roberto Orosei
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| Open AccessWidespread impact-generated porosity in early planetary crusts
Large impacts can create deep lying porosity far away from the crater. This result explains GRAIL’s findings and suggests impacts could support widespread fluid circulation, which has implications for habitable environments on early Earth and Mars.
- Sean E. Wiggins
- , Brandon C. Johnson
- & Simone Marchi
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Article
| Open AccessEarly crustal processes revealed by the ejection site of the oldest martian meteorite
A new study pinpoints the ejection site of the 4.5-Ga-old Martian breccia NWA 7034 and paired stones to an area northeast of the Terra 679 Cimmeria–Sirenium province.
- A. Lagain
- , S. Bouley
- & P. A. Bland
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Article
| Open AccessProposed energy-metabolisms cannot explain the atmospheric chemistry of Venus
The metabolisms proposed for hypothetical life in the clouds of Venus cannot explain the planet’s atmospheric chemistry and thus a limit can be placed on the maximum allowed biomass.
- Sean Jordan
- , Oliver Shorttle
- & Paul B. Rimmer
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Article
| Open AccessObservational evidence of ring current in the magnetosphere of Mercury
Ring currents have been observed in the magnetospheres of Earth, Jupiter, and Saturn. Here, the authors show observational evidence of Mercury’s ring current that is bifurcated because of the dayside off-equatorial magnetic minima.
- J.-T. Zhao
- , Q.-G. Zong
- & Y. Wei
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| Open AccessExogenic origin for the volatiles sampled by the Lunar CRater Observation and Sensing Satellite impact
The water and other volatiles observed in the LCROSS impact plume contained too much nitrogen to have originated from volcanic outgassing. These volatiles, stored in the top 1-3 meters of the Cabeus permanently shaded region, were delivered by comet impacts.
- K. E. Mandt
- , O. Mousis
- & A. Luspay-Kuti
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| Open AccessOrbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5
Although Trojan asteroids have been known for decades in other Solar System planets, only one Earth Trojan asteroid was detected. Here, the authors show that recently discovered 2020 XL5 is the second transient Earth Trojan asteroid.
- T. Santana-Ros
- , M. Micheli
- & L. Conversi
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| Open AccessThe Fe-FeSi phase diagram at Mercury’s core conditions
The iron-silicon phase diagram has been established at the conditions of Mercury’s core. The resulting phase diagram is remarkably complex, and presents an array of new mechanisms which may power Mercury’s inner dynamo.
- E. Edmund
- , G. Morard
- & D. Antonangeli
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Article
| Open AccessChemical heterogeneities reveal early rapid cooling of Apollo Troctolite 76535
Chemical heterogeneities in Apollo sample 76535 constrain the magmatic cooling history of the lunar Mg-suite to <~ 20 My. Such rapid cooling is inconsistent with a large intrusive magma body and suggests formation by reactive melt infiltration.
- William S. Nelson
- , Julia E. Hammer
- & G. Jeffrey Taylor
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Article
| Open AccessThe shallow structure of Mars at the InSight landing site from inversion of ambient vibrations
We invert Rayleigh wave ellipticity curves extracted from ambient seismic vibrations at the InSight landing site to resolve, for the first time on Mars, the shallow subsurface to around 200 m depth. While our seismic velocity model is largely consistent with the expected stacks of lava flows, we find a seismic low velocity zone at about 30 to 75 m depth that we interpret as a sedimentary layer sandwiched between layers of basalt flows.
- M. Hobiger
- , M. Hallo
- & W. B. Banerdt
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| Open AccessOccurrence rate of ultra-low frequency waves in the foreshock of Mercury increases with heliocentric distance
Low frequency waves are ubiquitous in space plasmas. Here, the authors show that the occurrence rate of ultra-low frequency waves associated with backstreaming ions in the Hermean foreshock increases with Mercury’s heliocentric distance.
- N. Romanelli
- & G. A. DiBraccio
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Article
| Open AccessThe Tharsis mantle source of depleted shergottites revealed by 90 million impact craters
The ejection sites of the martian meteorites are still unknown. Here, the authors build a database of 90 million craters and show that Tharsis region is the most likely source of depleted shergottites ejected 1.1 Ma ago, thus confirming that some portions of the mantle were recently anomalously hot.
- A. Lagain
- , G. K. Benedix
- & K. Miljković
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Perspective
| Open AccessThe search for lunar mantle rocks exposed on the surface of the Moon
Vast, ancient impact basins scattered mantle materials across the lunar surface. We review lunar evolution models to identify candidate mantle lithologies, then assess orbital observations to evalutae the current distribution of these materials and implications for fundamental planetary processes.
- Daniel P. Moriarty III
- , Nick Dygert
- & Noah E. Petro
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| Open AccessJarosite formation in deep Antarctic ice provides a window into acidic, water-limited weathering on Mars
The authors report in-situ formation of jarosite witin the Talos Dome ice core (East Antarctica) and show that this ferric-potassium sulfate mineral is present in ice deeper than 1000 meters and progressively increases with depth. This has implications for the presence and formation mechanisms of jarosite observed on Mars.
- Giovanni Baccolo
- , Barbara Delmonte
- & Massimo Frezzotti
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| Open AccessThe origin of the Moon’s Earth-like tungsten isotopic composition from dynamical and geochemical modeling
Tungsten isotopes between the Earth and Moon are compared in this new study. The authors find that traditional models of Moon formation are very unlikely to reproduce the Moon's Earth-like isotopic composition.
- Rebecca A. Fischer
- , Nicholas G. Zube
- & Francis Nimmo
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Article
| Open AccessA transient enhancement of Mercury’s exosphere at extremely high altitudes inferred from pickup ions
Mercury has a global dayside exosphere that is very tenuous and does not extend far from the planet. Here, the authors show enhancement of neutral densities at high altitudes inferred from pickup ions that is most likely caused by the impact of a meteroid.
- Jamie M. Jasinski
- , Leonardo H. Regoli
- & Neil Murphy
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Article
| Open AccessEffect of sulfur on sound velocity of liquid iron under Martian core conditions
Applying high-pressure and -temperature experiments, the authors here measure sound velocities in various liquid Fe-S alloys under conditions expected for the upper Martian core. The results together with future InSight mission data will help to understand whether the Martian core is molten Fe-S.
- Keisuke Nishida
- , Yuki Shibazaki
- & Kei Hirose
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| Open AccessSustained fluvial deposition recorded in Mars’ Noachian stratigraphic record
Using high-resolution orbital imagery of the Martian surface, the authors Salese et al. here describe the first discovered stratigraphic product of multiple extensive fluvial-channel belts in an exposed vertical section at Izola Mensa in the northwestern rim of the Hellas Basin.
- Francesco Salese
- , William J. McMahon
- & Maarten G. Kleinhans
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| Open AccessA magma ocean origin to divergent redox evolutions of rocky planetary bodies and early atmospheres
Applying first-principles molecular dynamic simulations and thermodynamic modelling, the authors suggest a vertical oxygen fugacity gradient in magma oceans of Earth, Mars, and the Moon. Consequently, the study proposes larger planets like Earth to have stronger oxidized upper mantles than smaller bodies such as Mars or the Moon.
- Jie Deng
- , Zhixue Du
- & Kanani K. M. Lee
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Article
| Open AccessLow cost satellite constellations for nearly continuous global coverage
Telecommunication, navigation and remote sensing services are highly dependent on how well satellites provide global coverage. Here the authors show a pair of four-satellite low-cost longer-life constellations that provide nearly continuous global coverage to support Earth observation.
- Lake A. Singh
- , William R. Whittecar
- & Patrick M. Reed
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| Open AccessThe impact origin and evolution of Chryse Planitia on Mars revealed by buried craters
Due to active geological resurfacing, the record of large impact basins (e.g. in Chryse Planitia) on Mars seems to be widely absent. Based on high-quality global datasets, the authors here propose a buried impact basin, covered by up to 1 km of sediments or lava flows after its formation more than 4 billion years ago.
- Lu Pan
- , Cathy Quantin-Nataf
- & Chloé Michaut
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Article
| Open AccessPlanetary-scale streak structure reproduced in high-resolution simulations of the Venus atmosphere with a low-stability layer
A planetary-scale streak structure in the Venusian lower-cloud layer was observed by the Akatsuki orbiter. Here the authors present numerical simulations that reproduce such structure and reveal that a low-stability layer, which induces baroclinic disturbances, is essential for its formation.
- Hiroki Kashimura
- , Norihiko Sugimoto
- & Yoshi-Yuki Hayashi
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| Open AccessMartian magmatism from plume metasomatized mantle
A unified model for the formation of martian rock types is required to understand Mars’s formation and evolution. Here the authors show that nakhlite and chassignite meteorites originate from melting of metasomatized depleted mantle lithosphere, whereas shergottite melts originate from deep plume sources.
- James M. D. Day
- , Kimberly T. Tait
- & Clive R. Neal
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| Open AccessImpact-induced changes in source depth and volume of magmatism on Mercury and their observational signatures
Mantle partial melting produced the volcanic crust of Mercury. Here, the authors numerically model the formation of post-impact melt sheets and find that mantle convection was weak at around 3.7–3.8 Ga and that the melt sheets of Caloris and Rembrandt may contain partial melting of pristine mantle material.
- Sebastiano Padovan
- , Nicola Tosi
- & Thomas Ruedas
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Article
| Open AccessClay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars
In the Gale Crater on Mars, organic matter has been detected, but in much lower concentrations than expected. Here, the authors conduct clay mineral synthesis experiments which suggest that clay minerals may rapidly form under oxidized conditions and thus explain the low organic concentrations in Gale Crater.
- Seth R. Gainey
- , Elisabeth M. Hausrath
- & Courtney L. Bartlett
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| Open AccessTaking the pulse of Mars via dating of a plume-fed volcano
Mars hosts the solar system’s largest volcanoes, but their formation rates remain poorly constrained. Here, the authors have measured the crystallization and ejection ages of meteorites from a Martian volcano and find that its growth rate was much slower than analogous volcanoes on Earth.
- Benjamin E. Cohen
- , Darren F. Mark
- & Caroline L. Smith
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Article
| Open AccessNew Martian valley network volume estimate consistent with ancient ocean and warm and wet climate
To understand the early Martian climate, the volume of the global Martian valley network is required. Here, the authors use a black top hat transformation method and find that the minimum global valley network volume is 1.74 × 1,014 m3 with a minimum cumulative volume of water required of 6.86 × 1,017 m3.
- Wei Luo
- , Xuezhi Cang
- & Alan D. Howard
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Article
| Open AccessSilica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile
Hydrothermal deposits on Mars may provide the best opportunity to find Martian biosignatures. Ruff and Farmer report that silica structures created by biotic and abiotic process in hot springs at El Tatio, Chile resemble those found in Gusev crater, thus making it an ideal location for future missions.
- Steven W. Ruff
- & Jack D. Farmer
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Article
| Open AccessSesquinary catenae on the Martian satellite Phobos from reaccretion of escaping ejecta
The origin of the numerous linear grooves and craters that litter the Martian moon Phobos' surface remains enigmatic. Here, by modelling low-velocity escaping ejecta from impacts to Phobos, the authors show that several of these chains can be explained by reimpacting sesquinary ejecta shortly after ejection.
- M. Nayak
- & E. Asphaug
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Article
| Open AccessReconstructing the transport history of pebbles on Mars
The discovery of rounded pebbles by Curiosity suggests sustained fluvial activity existed on Mars, but interpretations have been qualitative. Here, the authors show that transport distance can be calculated on the basis of pebble shape alone, suggesting they travelled 10 s of km by bed-load transport.
- Tímea Szabó
- , Gábor Domokos
- & Douglas J. Jerolmack
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Determining volcanic eruption styles on Earth and Mars from crystallinity measurements
Although observations of volcanic deposits on Mars are more accessible than ever, constraining Martian eruption styles remains a challenge. Here, the authors show that volcanic eruption style can be characterized through X-ray diffraction analysis of groundmass crystallinity in basaltic volcanic deposits.
- Kellie T. Wall
- , Michael C. Rowe
- & Jennifer D. Eccles
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Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux
Although the Martian landscape presents evidence of wind erosion, sand-moving winds on Mars were thought to be rare due to the thin atmosphere. Here, the authors show that sand transport occurs daily and that the resulting sand flux varies seasonally.
- F. Ayoub
- , J.-P. Avouac
- & N.T. Bridges
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Dawn–dusk asymmetry in the Kelvin–Helmholtz instability at Mercury
Recently, the NASA MESSENGER mission reported signatures of Kelvin–Helmholtz instabilities in the magnetic environment of Mercury. Using global hybrid kinetic simulations, Paral and Rankin reproduce these observations, revealing a dawn–dusk asymmetry in the instability.
- Jan Paral
- & Robert Rankin