Filter By:

Article Type
  • Non-thermal, hard X-ray bremsstrahlung emission from auroral regions is detected at Jupiter by the NuSTAR instrument. Simultaneous in situ observations from the Juno spacecraft confirm the signatures of acceleration from non-thermal electrons and highlight the similarities with auroral processes on Earth.

    • Kaya Mori
    • Charles Hailey
    • Licia Ray
  • Laboratory experiments show that the type of iron mineral is the dominant factor controlling the chlorate/perchlorate (ClO3/ClO4) generation ratio on Mars over oxidation methods or atmospheric composition. Chlorate yields are found to exceed perchlorate yields by orders of magnitude in the current desiccated Martian conditions.

    • Shuai-Yi Qu
    • Yu-Yan Sara Zhao
    • Jian-Zhong Liu
  • To enable sub-arcsecond precision imaging of the radio sky, the Earth’s corrupting ionosphere must be corrected for. Here, the authors perform this challenging task, yielding a 6.6 deg2 field of view of the Lockman Hole field at sub-arcsecond resolution.

    • F. Sweijen
    • R. J. van Weeren
    • A. P. Thomson
  • The episodic but protracted delivery of foundering cold material (diapirs) to the lunar core during the first billion years activated vigorous core convection that generated peaks of high intensity in the magnetic field. This process can explain the magnetic record of lunar rocks.

    • Alexander J. Evans
    • Sonia M. Tikoo
  • The 2,000-au-long streamer of material from binary protostar Z CMa can be explained by the flyby of an object some 4,700 au away, now revealed through high-spatial-resolution ALMA and JVLA observations.

    • Ruobing Dong
    • Hauyu Baobab Liu
    • Motohide Tamura
  • High-spectral-resolution data from the CARMENES spectrometer could resolve the neutral oxygen triple line at 777.4 nm in the atmosphere of ultrahot Jupiter KELT-9b. The results show the presence of non-local thermodynamic equilibrium processes and reveal macro- and microturbulence induced by fast winds with speeds ranging between 3 and 13 km s−1.

    • Francesco Borsa
    • Luca Fossati
    • Denis Shulyak
  • An evolutionary model of the solar protoplanetary disk that includes the decrease of its viscosity with time and the accretion of gas from the interstellar medium shows that planetesimals formed simultaneously in two locations: at the water snowline (~5 au) and at the silicate sublimation line (~1 au), explaining the observed isotopic dichotomy of iron meteorites.

    • A. Morbidelli
    • K. Baillié
    • T. Kleine
  • The MicrOmega imaging spectrometer performed a first characterization of the sample returned from asteroid Ryugu by Hayabusa2. Compositional homogeneity dominates down to millimetre scales, with signatures of hydrated phases and organics. At the submillimetre scale, NH-rich compounds and alteration products such as carbonates are detected.

    • C. Pilorget
    • T. Okada
    • J.-P. Bibring
  • The Hayabusa2 spacecraft returned 5.4 g of material from the asteroid Ryugu. A first analysis of the samples found an estimated density of 1,282 ± 231 kg m−3, considerably lower than even the most porous meteorites. Together with preliminary spectral analysis, these results indicate that Ryugu is similar to CI chondrites, but darker, more porous and more brittle.

    • Toru Yada
    • Masanao Abe
    • Yuichi Tsuda
    LetterOpen Access