Astronomy and planetary science

  • Article
    | Open Access

    Lunar impact basins formed during the magma ocean solidification should have formed almost unidentifiable topographic and crustal thickness signatures, thus may escape detection. This result allows for a higher impact flux in the earliest epoch of Earth-Moon evolution.

    • K. Miljković
    • , M. A. Wieczorek
    •  & M. T. Zuber
  • Article
    | Open Access

    Ultramafic olivine-rich achondrites provide insight into the missing mantle problem in the asteroid belt. The petrology and geochemistry of these samples suggests they are related to Vesta or the Vestoids.

    • Zoltan Vaci
    • , James M. D. Day
    •  & Andreas Pack
  • Perspective
    | Open Access

    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
  • Article
    | Open Access

    The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H2S.

    • Yarui Zhao
    • , Zijie Luo
    •  & Xueming Yang
  • Article
    | Open Access

    Meteorites from space often include denser polymorphs of their minerals, providing records of past hypervelocity collisions. An olivine mineral crystal was shock-compressed by a high-power laser, and its transformation into denser ringwoodite was time-resolved using an X-ray free electron laser.

    • Takuo Okuchi
    • , Yusuke Seto
    •  & Norimasa Ozaki
  • Article
    | Open Access

    Gravity waves are observed in Venus atmosphere, but their characteristics are not well-known. Here, the authors show spontaneous generation of gravity waves from the thermal tides in the Venus atmosphere as small-scale gravity waves are resolved in high-resolution general circulation model.

    • Norihiko Sugimoto
    • , Yukiko Fujisawa
    •  & Yoshi-Yuki Hayashi
  • Article
    | Open Access

    Superbolts are powerful, rare lightning events. Here, the authors show simultaneous satellite and ground measurements of a superbolt, and demonstrate different properties of superbolts and lightnings.

    • J.-F. Ripoll
    • , T. Farges
    •  & S. Pédeboy
  • Article
    | Open Access

    Several scenarios exist to explain the origins of the organic matter found in carbonaceous chondrites. Here, the authors show laboratory experiments confirming that a significant portion of the soluble organic matter can originate from organic ices inherited from the dense molecular cloud.

    • G. Danger
    • , V. Vinogradoff
    •  & P. Schmitt-Kopplin
  • Article
    | Open Access

    It was predicted that Alfvén waves can account for the acceleration of precipitating auroral electrons. Here, the authors show laboratory measurements of the resonant transfer of energy from Alfvén waves to electrons under conditions relevant to the auroral zone as a direct test.

    • J. W. R. Schroeder
    • , G. G. Howes
    •  & S. Dorfman
  • Article
    | Open Access

    The authors here propose a chemical reaction that forms ammoniated phyllosilicates on Ceres. This process could trigger at a very low temperature, suggesting Ceres evolution in a region different from its current location.

    • Santosh K. Singh
    • , Alexandre Bergantini
    •  & Ralf I. Kaiser
  • Article
    | Open Access

    Three-body dissociation of water, producing one oxygen and two hydrogen atoms, has been difficult to investigate due to the lack of intense vacuum ultraviolet sources. Here, using a tunable free-electron laser, the authors obtain quantum yields for this channel showing that it is a possible route to prebiotic oxygen formation in interstellar environments.

    • Yao Chang
    • , Yong Yu
    •  & Xueming Yang
  • Article
    | Open Access

    The authors describe a dynamic surface instability between impacting materials, showing that a region of mixing grows between two media. The study implies that this can explain mixed compositions and textures in certain meteorites.

    • Avi Ravid
    • , Robert I. Citron
    •  & Raymond Jeanloz
  • Article
    | Open Access

    Polarimetry provides information about physical characteristics of cometary dust. Here, the authors show that the polarization of interstellar comet 2I/Borisov exceeds the typical values for comets, and this together with its polarimetrically homogenous coma suggests a more pristine nature of the object.

    • S. Bagnulo
    • , A. Cellino
    •  & M. Devogèle
  • Article
    | Open Access

    During geomagnetic substorms, the energy accumulated from solar wind is abruptly transported to ionosphere. Here, the authors show application of community detection on the time-varying networks constructed from all magnetometers collaborating with the SuperMAG initiative.

    • L. Orr
    • , S. C. Chapman
    •  & W. Guo
  • Article
    | Open Access

    Based on the analysis of chemical maps of Thorium and Potassium derived in the Eridania region on Mars, the authors show how radiogenic heat driven hydrothermal systems may have persisted on Mars.

    • Lujendra Ojha
    • , Suniti Karunatillake
    •  & Jacob Buffo
  • Article
    | Open Access

    Hurricanes in the Earth’s low atmosphere are known, but not detected in the upper atmosphere earlier. Here, the authors show a long-lasting hurricane in the polar ionosphere and magnetosphere with large energy and momentum deposition despite otherwise extremely quiet conditions.

    • Qing-He Zhang
    • , Yong-Liang Zhang
    •  & Li-Dong Xia
  • Article
    | Open Access

    Evolution of accretion disk and corona during outbursts in black hole binary systems is still unclear. Here, the authors show spectral analysis of MAXI J1820+070 and propose a scenario of a dynamical corona to explain the evolution of the reflection fraction observed by Insight-HXMT.

    • Bei You
    • , Yuoli Tuo
    •  & Yue Zhu
  • Article
    | Open Access

    Imaging of low-mass exoplanets can be achieved once the thermal background in the mid-infrared (MIR) wavelengths can be mitigated. Here, the authors present a ground-based MIR observing approach enabling imaging low-mass temperate exoplanets around nearby stars.

    • K. Wagner
    • , A. Boehle
    •  & T. de Zeeuw
  • Article
    | Open Access

    Seasonally averaged energy input into the ionosphere from geospace is generally considered to be symmetric. Here, the authors show preference for electromagnetic energy input at 450 km altitude into the northern hemisphere, on both the dayside and the nightside, when averaged over season.

    • I. P. Pakhotin
    • , I. R. Mann
    •  & D. J. Knudsen
  • Article
    | Open Access

    This manuscript tackles the origin of organic molecules in carbonaceous meteorites. Identifying hexamethylenetetramine in three carbonaceous meteorites, the authors propose formation from ammonia and formaldehyde by photochemical and thermal reactions in the interstellar medium, followed by the incorporation into planetary systems.

    • Yasuhiro Oba
    • , Yoshinori Takano
    •  & Shogo Tachibana
  • Article
    | Open Access

    In the habitable zone concept, a planet’s carbon dioxide-water greenhouse maintains surface liquid water. Here, the authors estimate how many Earthlike exoplanets are needed to detect a relationship between stellar flux and the atmospheric carbon dioxide predicted by carbon cycle modeling.

    • Owen R. Lehmer
    • , David C. Catling
    •  & Joshua Krissansen-Totton
  • Article
    | Open Access

    The discrepancy between the optical and X-ray properties of tidal disruption events (TDE) is an unresolved issue. Here, the authors show delayed X-ray brightening after the optical flare in TDE OGLE16aaa followed by several flux dips during the decay phase that could be explained by the presence of supermassive black hole binary or patchy obscuration.

    • Xinwen Shu
    • , Wenjie Zhang
    •  & Tinggui Wang
  • Article
    | Open Access

    Establishing diagnostics for terrestrial exoplanets are crucial for their characterization. Here, the authors show brightness modulations of Venus are caused by planetary-scale waves superimposed on the super-rotating winds can be used to detect existence of an atmosphere if detected at an exoplanet.

    • Y. J. Lee
    • , A. García Muñoz
    •  & S. Watanabe
  • Article
    | Open Access

    The location of energy dissipation in powerful extragalactic jets is currently unknown. Here, the authors show that the more distant molecular torus is the dominant location for powerful jets using a diagnostic called the seed factor which is dependent only on observable quantities.

    • Adam Leah W. Harvey
    • , Markos Georganopoulos
    •  & Eileen T. Meyer
  • Article
    | Open Access

    Adaptive optics wavefront sensors need to be in a pupil plane and are insensitive to certain wavefront-error modes. The authors present a wavefront sensor based on a photonic lantern fibre-mode-converter and deep learning, which can be placed at the same focal plane accessing nondegenerate wavefront information and reconstructing the wavefront.

    • Barnaby R. M. Norris
    • , Jin Wei
    •  & Sergio G. Leon-Saval
  • Article
    | Open Access

    Very-Low-Frequency (VLF) communication transmitters, operate worldwide, radiate emissions at particular frequencies 10-30 kHz. Here, the authors show VLF transmitter emissions that leak from the Earth’s ground are primarily responsible for bifurcating the energetic electron belt over 20–100 keV.

    • Man Hua
    • , Wen Li
    •  & Geoffrey D. Reeves
  • Article
    | Open Access

    Calcium and oxygen are abundant elements in the Earth’s mantle, largely present as calcium oxide. Here the authors show, by experiments and computations, that calcium ozonide (CaO3) is stabilized at the high pressures and temperatures characteristic of the lower mantle, with implications for the deep Earth’s chemistry.

    • Yanchao Wang
    • , Meiling Xu
    •  & Yanming Ma
  • Article
    | Open Access

    Electrons in the Van Allen radiation belts can have energies in excess of 7 MeV, however, the energization mechanism is debated. Here, the authors show phase space density peaks in magnetic coordinate space as a way of analyzing satellite observations which demonstrates that local acceleration is capable of heating electrons up to 7 MeV.

    • Hayley J. Allison
    •  & Yuri Y. Shprits
  • Article
    | Open Access

    Blazars show variable non-thermal emission across the electromagnetic spectrum from radio waves to gamma rays. Here, the authors show blazar 3C 279 reveals a characteristic peak-in-peak variability pattern on time scales of minutes if particle acceleration is due to relativistic magnetic reconnection.

    • A. Shukla
    •  & K. Mannheim
  • Article
    | Open Access

    Kilonovae observations can be used to out constraints on the Hubble constant (H0). Here, the authors show H0 measurements by combining light curves of four short gamma-ray burts with GW170817 are about a factor of 2-3 more precise than the standard-siren measurements using only gravitational-waves.

    • Michael W. Coughlin
    • , Sarah Antier
    •  & Nandita Khetan
  • Article
    | Open Access

    Dawn mission’s second extended phase provided high resolution observations of Occator crater of the dwarf planet Ceres. Here, the authors show stereo imaging and topographic maps of this crater revealing the influence of crustal composition on impact related melt and hydrothermal processes, and compare features to those on Mars, Earth and the Moon.

    • P. Schenk
    • , J. Scully
    •  & C. Raymond
  • Article
    | Open Access

    The second extended phase of the Dawn mission provided high resolution observations of Occator crater of the dwarf planet Ceres. Here, the authors show that the central faculae were sourced in an impact-induced melt chamber, with a contribution from the deep brine reservoir, while the Vinalia Faculae were sourced by the deep brine reservoir alone.

    • J. E. C. Scully
    • , P. M. Schenk
    •  & C. T. Russell
  • Article
    | Open Access

    Magnetic reconnection is a fundamental plasma process of magnetic energy conversion to kinetic energy. Here, the authors show direct evidence of secondary reconnection in the filamentary currents within the flux ropes indicating a significant contribution to energy conversion in the kinetic scale during turbulent reconnection.

    • Shimou Wang
    • , Rongsheng Wang
    •  & Shui Wang
  • Article
    | Open Access

    Space debris laser ranging is a technique to measure distances to defunct satellites or rocket bodies in orbits around Earth which was only possible within a few hours around twilight. Here, the authors show the first space debris laser ranging results during daylight while correcting inaccurate predictions using a real-time target detection software.

    • Michael A. Steindorfer
    • , Georg Kirchner
    •  & Tim Flohrer
  • Article
    | Open Access

    Current models of Galactic chemical evolution under predict the phosphorus we observe in our Solar System. Here, the authors show the discovery of 15 phosphorus-rich stars with a peculiar abundance pattern that challenges the present stellar nucleosynthesis theoretical predictions, but which could explain the missing source of phosphorus in the Galaxy.

    • Thomas Masseron
    • , D. A. García-Hernández
    •  & Carlos Dafonte