Research articles

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  • Experiments are presented that indicate that methane can be produced abiotically on Mars through the photocatalytic reaction of CO2, in a process called methanogenesis. Methane can then be shocked (through impacts) to form RNA nucleobases and glycine.

    • Svatopluk Civiš
    • Antonín Knížek
    • Martin Ferus
    Article
  • The relatively unexplored southwestern region of the Large Magellanic Cloud is host to a massive, embedded star-forming complex that rivals the star-forming efficiency of 30 Doradus. Its most luminous object could be a super star cluster in formation.

    • Bram B. Ochsendorf
    • Hans Zinnecker
    • Mubdi Rahman
    Letter
  • Chloromethane (CH3Cl) has been observed towards a low-mass protostar and comet 67P, making it the first organohalogen detected in space. The species was previously considered to be a biomarker, but the authors suggest viable alternative abiotic formation routes.

    • Edith C. Fayolle
    • Karin I. Öberg
    • C. -Y. Tzou
    Letter
  • Optical pulsations from a millisecond pulsar that had transitioned from a rotationally powered regime to an accretion disk state have been detected. The optical emission is likely to be due to electron synchrotron emission in a rotation-powered magnetosphere.

    • F. Ambrosino
    • A. Papitto
    • L. Riverol
    Letter
  • By assessing the ionization fraction of the environment around Tycho’s (type Ia) supernova, the authors have constrained the properties of its progenitor enough to rule out a hot, luminous white dwarf. A double white dwarf binary merger is allowed.

    • T. E. Woods
    • P. Ghavamian
    • M. Gilfanov
    Article
  • A candidate dual supermassive black hole system with a projected separation of 0.35 pc is found in the gas-rich interacting spiral galaxy NGC 7674, evidenced by a ∼0.7 kpc Z-shaped radio jet and two, possibly inverted-spectrum, compact radio cores.

    • P. Kharb
    • D. V. Lal
    • D. Merritt
    Article
  • The authors present a spectrophotometric and hydrodynamical study of supernova OGLE-2014-SN-073, which had remarkably high inferred ejecta mass and energy, potentially higher than can be explained with canonical core-collapse neutrino-driven explosions.

    • G. Terreran
    • M. L. Pumo
    • K. Ulaczyk
    Article
  • The polarization resulting from electron scattering in a stellar atmosphere has been detected towards the rapidly spinning star Regulus. Deformation of the star from spherical allows this effect to be seen, fulfilling a prediction from around 50 years ago.

    • Daniel V. Cotton
    • Jeremy Bailey
    • J. H. Hough
    Letter
  • A tight correlation between gamma rays and optical emission in nova ASASSN-16ma indicates that the optical light comes from reprocessed emission from shocks in the ejecta, rather than an energy release near the hot white dwarf, as in the standard model.

    • Kwan-Lok Li
    • Brian D. Metzger
    • Hiroshi Itoh
    Letter
  • Recent observations reveal tension between various cosmological probes. Assuming dark energy to be non-constant, depending on redshift, may relieve this tension. The Dark Energy Spectroscopic Instrument survey will be able to confirm this result.

    • Gong-Bo Zhao
    • Marco Raveri
    • Hanyu Zhang
    Letter
  • Brightness changes of the Sun over timescales from minutes to decades, relevant to Earth’s climate and the detection of exoplanets around Sun-like stars, can be fully and precisely explained by the magnetic field and granulation of the Sun’s surface.

    • A. I. Shapiro
    • S. K. Solanki
    • W. K. Schmutz
    Letter