Research articles

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  • The sample taken from carbonaceous asteroid Ryugu and brought back to Earth by the Hayabusa2 spacecraft contains outer Solar System-derived materials uncontaminated by terrestrial processes. Even CI carbonaceous chondrites, despite their closeness to solar abundances, are not pristine.

    • Motoo Ito
    • Naotaka Tomioka
    • Yuichi Tsuda
    Article Open Access
  • Some fragments of the Aguas Zarcas carbonaceous meteorite have been shocked before being redeposited over an unshocked lithology. As their size distribution is similar to that of the ejecta observed at Bennu, they might be the signature of activity of the Aguas Zarcas parent body. Alternatively, they might be the result of a large-scale impact.

    • Xin Yang
    • Romy D. Hanna
    • Philipp R. Heck
    Article
  • Each uncontrolled rocket body in orbit poses a low casualty risk on reentry. But the cumulative risk is unacceptable and disproportionately borne by the Global South. Spacefaring states must stop exporting these risks and plan for safer reentries.

    • Michael Byers
    • Ewan Wright
    • Cameron Byers
    Analysis Open Access
  • Modelling shows that electrostatic lofting removes the finer particles from the asteroid regolith layer efficiently for kilometre-sized or smaller bodies, creating the boulder-dominated surfaces seen on Bennu or Ryugu. On larger bodies, the formation of fine regolith via weathering effects dominates instead.

    • Hsiang-Wen Hsu
    • Xu Wang
    • Mihály Horányi
    Article
  • N-body simulations show that the Earth might have accreted stochastically from various precursor bodies with different compositions depending on their formation temperature. This scenario fits the elemental isotope composition of the bulk Earth and suggests the presence of a radial gradient in the composition of the protoplanetary disk.

    • Paolo A. Sossi
    • Ingo L. Stotz
    • Hugh St. C. O’Neill
    Article
  • Recent detections of nitrogen-bearing polycyclic aromatic hydrocarbons (N-PAHs) in the interstellar medium prompt questions about how these molecules form at low temperatures. Here a combination of kinetic studies and spectroscopy reveals an efficient formation route from monocyclic aromatic hydrocarbons to N-PAHs.

    • Daniël B. Rap
    • Johanna G. M. Schrauwen
    • Sandra Brünken
    Article
  • A hypermodel approach is used to analyse gravitational-wave signals under multiple models simultaneously, enabling the data-driven study of systematic modelling errors. The authors verify the approach on existing observations of the two observed binary neutron star merger signals GW170817 and GW190425 and a third candidate event.

    • Gregory Ashton
    • Tim Dietrich
    Article
  • Fast radio bursts (FRBs) can be used as sensitive probes of diffuse gas in galaxy dark-matter haloes. Here the authors analyse several fast radio bursts that intersect galaxy dark-matter haloes within 40 Mpc, finding that the additional dispersion provided by the diffuse gas (presumably the intragroup medium) is in excess of 90 pc cm−3.

    • Liam Connor
    • Vikram Ravi
    Letter
  • In 1933, Fritz Zwicky's measurement of the Coma cluster's mass led him to infer the existence of dark matter. The present work applies a new deep learning approach to revisit Zwicky's original measurement and demonstrate the progress of modern astronomy.

    • Matthew Ho
    • Michelle Ntampaka
    • Hy Trac
    Letter
  • Harnessing the resolving power of space very long baseline interferometry results in a link between 22 GHz H2O MegaMaser emission and accretion activity in the thin disc around the nucleus of galaxy NGC 4258. The emission regions appear consistent with a periodic magneto-rotational instability in the disc.

    • Willem A. Baan
    • Tao An
    • Andrej Sobolev
    Article
  • Big-data labelling is critical to harness the power of supervised machine learning in astronomy. Neural networks applied to the solar flux emergence problem considerably reduce the manual labelling burden and easily extract higher-level information.

    • Subhamoy Chatterjee
    • Andrés Muñoz-Jaramillo
    • Derek A. Lamb
    Article
  • Modelling of Earth- or super-Earth-sized planets with a thick H–He atmosphere shows that the hydrogen collision-induced absorptions in the infrared wavelength can make the planet amenable to hosting surface liquid water for several billion years, thus creating a long-term potentially habitable environment.

    • Marit Mol Lous
    • Ravit Helled
    • Christoph Mordasini
    Article Open Access