Volume 1 Issue 8, 1 August 2017

Letter

  • Letter |

    Low-mass black holes that accrete stars from locally dense environments grow over the Hubble time above a minimal mass of 105 solar masses, independently of their initial mass. This explains why there are no convincing cases of intermediate-mass black holes to date.

    • Tal Alexander
    •  & Ben Bar-Or

    Insight:

  • Letter |

    Combining studies of star formation rates with studies of cloud–magnetic field alignment has revealed that magnetic fields are a primary regulator of star formation. Perpendicular alignment inhibits star formation, whereas parallel alignment facilitates it.

    • Hua-bai Li
    • , Hangjin Jiang
    • , Xiaodan Fan
    • , Qilao Gu
    •  & Yapeng Zhang
  • Letter |

    Multiple stars are thought to form either through disk fragmentation or turbulent fragmentation, but the latter has had no clear observational confirmation. Here the authors report misaligned disks around a wide-binary pair, a sign of turbulent fragmentation.

    • Jeong-Eun Lee
    • , Seokho Lee
    • , Michael M. Dunham
    • , Ken’ichi Tatematsu
    • , Minho Choi
    • , Edwin A. Bergin
    •  & Neal J. Evans
  • Letter |

    Most of the Mars Trojans — asteroids co-orbiting the planet — are dynamically related; thus, they have a common origin. Joint information from spectral observations and dynamical modelling suggests that they were ejected from Mars itself after an impact.

    • D. Polishook
    • , S. A. Jacobson
    • , A. Morbidelli
    •  & O. Aharonson
  • Letter |

    M dwarfs harbour stellar dynamos driven by convective motions in their interiors. Previously, the magnetic field strengths generated by these dynamos were thought to saturate at 4 kG, but this limit has now been busted by four stars with dipole dynamo states.

    • D. Shulyak
    • , A. Reiners
    • , A. Engeln
    • , L. Malo
    • , R. Yadav
    • , J. Morin
    •  & O. Kochukhov
  • Letter |

    Some star clusters in the Large Magellanic Cloud have extended main-sequence turnoffs, suggesting that the component stars have different ages. However, if the blue main-sequence stars were initially spinning rapidly, and experienced braking, the apparent age difference disappears.

    • Francesca D’Antona
    • , Antonino P. Milone
    • , Marco Tailo
    • , Paolo Ventura
    • , Enrico Vesperini
    •  & Marcella Di Criscienzo
  • Letter |

    Venus Express wind measurements at Venus’s cloud top during the night show a different picture than dayside. Both fast and slow motions are detected (there are only fast ones during the day) as well as many stationary waves related to surface relief.

    • J. Peralta
    • , R. Hueso
    • , A. Sánchez-Lavega
    • , Y. J. Lee
    • , A. García Muñoz
    • , T. Kouyama
    • , H. Sagawa
    • , T. M. Sato
    • , G. Piccioni
    • , S. Tellmann
    • , T. Imamura
    •  & T. Satoh

Article

  • Article |

    A previously unidentified class of variable stars has been found in OGLE survey data, characterized by periodic brightness variations on ~30-min timescales, amplitudes of ~0.3 mag and temperatures of ~30,000 K. They are potentially evolved low-mass stars.

    • Paweł Pietrukowicz
    • , Wojciech A. Dziembowski
    • , Marilyn Latour
    • , Rodolfo Angeloni
    • , Radosław Poleski
    • , Francesco di Mille
    • , Igor Soszyński
    • , Andrzej Udalski
    • , Michał K. Szymański
    • , Łukasz Wyrzykowski
    • , Szymon Kozłowski
    • , Jan Skowron
    • , Dorota Skowron
    • , Przemek Mróz
    • , Michał Pawlak
    •  & Krzysztof Ulaczyk

Mission Control

  • Mission Control |

    NASA's New Horizons mission to the outer Solar System has revolutionized our understanding of the Pluto–Charon system. But, Richard P. Binzel explains, this is only half the story of this intrepid spacecraft, as it voyages even further through the Kuiper Belt.

    • Richard P. Binzel

Research Highlight

Review Article

  • Review Article |

    Total solar eclipses are a unique opportunity to study the lower solar corona where the solar wind originates. This review presents the recent advancements in coronal science from eclipses and the scientific and outreach plans for this year's totality.

    • Jay M. Pasachoff

Obituary

  • Obituary |

    Giovanni Fabrizio Bignami, ‘Nanni’ to his friends, suddenly passed away on 25 May 2017. A pioneer in the field of gamma-ray astrophysics, he identified Geminga: a mysterious, radio quiet, gamma-ray pulsar. He was an undisputed leader, manager, maestro, colleague and friend.

    • Pietro Ubertini

News & Views

Comment

  • Comment |

    Active galactic nuclei (AGNs) are empirically divided into ‘radio-loud’ and ‘radio-quiet’. These 50-year-old labels are obsolete, misleading and wrong. I argue that AGNs should be classified as ‘jetted’ and ‘non-jetted’ based on a physical difference — the presence (or lack) of strong relativistic jets.

    • Paolo Padovani

    Insight:

Books & Arts