Letters

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  • Letter |

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) looked at the Moon in the 6 µm wavelength region and found a signature of molecular water, distinguishing it from other forms of hydration. The authors estimate water abundances between 100 and 400 µg g1 at high latitudes, trapped within impact glasses or possibly in between grains.

    • C. I. Honniball
    • , P. G. Lucey
    • , S. Li
    • , S. Shenoy
    • , T. M. Orlando
    • , C. A. Hibbitts
    • , D. M. Hurley
    •  & W. M. Farrell
  • Letter |

    The distribution of boulders on the surface of top-shaped asteroids such as Bennu or Ryugu tells us about the processes driving their evolution. A model shows that the spin-up induced by the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect can explain simultaneously both the latitudinal behaviour of the boulders and the regolith migration.

    • Bin Cheng
    • , Yang Yu
    • , Erik Asphaug
    • , Patrick Michel
    • , Derek C. Richardson
    • , Masatoshi Hirabayashi
    • , Makoto Yoshikawa
    •  & Hexi Baoyin
  • Letter |

    Soft X-ray observations of the southern Galactic sky with the HaloSat CubeSat indicate that the circumgalactic medium (CGM) of the Milky Way has a disk-like profile, with an extended spherical halo. Clumps in the CGM correlate with star-formation activity.

    • P. Kaaret
    • , D. Koutroumpa
    • , K. D. Kuntz
    • , K. Jahoda
    • , J. Bluem
    • , H. Gulick
    • , E. Hodges-Kluck
    • , D. M. LaRocca
    • , R. Ringuette
    •  & A. Zajczyk
  • Letter |

    Realistic three-dimensional magneto-thermal simulations of magnetars with strong, large-scale toroidal magnetic fields accurately describe the observed light curves of 10 out of 19 magnetars in quiescence and allow their rotational orientation to be further constrained.

    • Andrei P. Igoshev
    • , Rainer Hollerbach
    • , Toby Wood
    •  & Konstantinos N. Gourgouliatos
  • Letter |

    A shape evolution model shows that bilobed Arrokoth obtained its peculiar flattened shape by sublimation-driven mass loss. This process happened very early in the body’s history and may be a widespread shaping mechanism of Kuiper belt objects.

    • Y. Zhao
    • , L. Rezac
    • , Y. Skorov
    • , S. C. Hu
    • , N. H. Samarasinha
    •  & J.-Y. Li
  • Letter |

    Six bright boulders of exotic material on near-Earth asteroid (101955) Bennu stand out from the average asteroidal surface. This unexpected record of impactors offers clues to the formation history of Bennu.

    • D. N. DellaGiustina
    • , H. H. Kaplan
    • , A. A. Simon
    • , W. F. Bottke
    • , C. Avdellidou
    • , M. Delbo
    • , R.-L. Ballouz
    • , D. R. Golish
    • , K. J. Walsh
    • , M. Popescu
    • , H. Campins
    • , M. A. Barucci
    • , G. Poggiali
    • , R. T. Daly
    • , L. Le Corre
    • , V. E. Hamilton
    • , N. Porter
    • , E. R. Jawin
    • , T. J. McCoy
    • , H. C. Connolly Jr
    • , J. L. Rizos Garcia
    • , E. Tatsumi
    • , J. de Leon
    • , J. Licandro
    • , S. Fornasier
    • , M. G. Daly
    • , M. M. Al Asad
    • , L. Philpott
    • , J. Seabrook
    • , O. S. Barnouin
    • , B. E. Clark
    • , M. C. Nolan
    • , E. S. Howell
    • , R. P. Binzel
    • , B. Rizk
    • , D. C. Reuter
    •  & D. S. Lauretta
  • Letter |

    The Hayabusa2 team has discovered two types of bright boulder on the dark, carbonaceous asteroid Ryugu. One type has a spectrum consistent with material from an anhydrous silicate-rich asteroid, likely introduced by one or more collisions in Ryugu’s past.

    • E. Tatsumi
    • , C. Sugimoto
    • , L. Riu
    • , S. Sugita
    • , T. Nakamura
    • , T. Hiroi
    • , T. Morota
    • , M. Popescu
    • , T. Michikami
    • , K. Kitazato
    • , M. Matsuoka
    • , S. Kameda
    • , R. Honda
    • , M. Yamada
    • , N. Sakatani
    • , T. Kouyama
    • , Y. Yokota
    • , C. Honda
    • , H. Suzuki
    • , Y. Cho
    • , K. Ogawa
    • , M. Hayakawa
    • , H. Sawada
    • , K. Yoshioka
    • , C. Pilorget
    • , M. Ishida
    • , D. Domingue
    • , N. Hirata
    • , S. Sasaki
    • , J. de León
    • , M. A. Barucci
    • , P. Michel
    • , M. Suemitsu
    • , T. Saiki
    • , S. Tanaka
    • , F. Terui
    • , S. Nakazawa
    • , S. Kikuchi
    • , T. Yamaguchi
    • , N. Ogawa
    • , G. Ono
    • , Y. Mimasu
    • , K. Yoshikawa
    • , T. Takahashi
    • , Y. Takei
    • , A. Fujii
    • , Y. Yamamoto
    • , T. Okada
    • , C. Hirose
    • , S. Hosoda
    • , O. Mori
    • , T. Shimada
    • , S. Soldini
    • , R. Tsukizaki
    • , T. Mizuno
    • , T. Iwata
    • , H. Yano
    • , M. Ozaki
    • , M. Abe
    • , M. Ohtake
    • , N. Namiki
    • , S. Tachibana
    • , M. Arakawa
    • , H. Ikeda
    • , M. Ishiguro
    • , K. Wada
    • , H. Yabuta
    • , H. Takeuchi
    • , Y. Shimaki
    • , K. Shirai
    • , N. Hirata
    • , Y. Iijima
    • , Y. Tsuda
    • , S. Watanabe
    •  & M. Yoshikawa
  • Letter |

    LTT 9779 b is Neptune-sized planet rotating around its star with a period of 0.79 days and an equilibrium temperature of 2,000 K. It is not clear how it retained its atmospheric envelope, which contains ~10% of H/He, as it should have been photoevaporated by now.

    • James S. Jenkins
    • , Matías R. Díaz
    • , Nicolás T. Kurtovic
    • , Néstor Espinoza
    • , Jose I. Vines
    • , Pablo A. Peña Rojas
    • , Rafael Brahm
    • , Pascal Torres
    • , Pía Cortés-Zuleta
    • , Maritza G. Soto
    • , Eric D. Lopez
    • , George W. King
    • , Peter J. Wheatley
    • , Joshua N. Winn
    • , David R. Ciardi
    • , George Ricker
    • , Roland Vanderspek
    • , David W. Latham
    • , Sara Seager
    • , Jon M. Jenkins
    • , Charles A. Beichman
    • , Allyson Bieryla
    • , Christopher J. Burke
    • , Jessie L. Christiansen
    • , Christopher E. Henze
    • , Todd C. Klaus
    • , Sean McCauliff
    • , Mayuko Mori
    • , Norio Narita
    • , Taku Nishiumi
    • , Motohide Tamura
    • , Jerome Pitogo de Leon
    • , Samuel N. Quinn
    • , Jesus Noel Villaseñor
    • , Michael Vezie
    • , Jack J. Lissauer
    • , Karen A. Collins
    • , Kevin I. Collins
    • , Giovanni Isopi
    • , Franco Mallia
    • , Andrea Ercolino
    • , Cristobal Petrovich
    • , Andrés Jordán
    • , Jack S. Acton
    • , David J. Armstrong
    • , Daniel Bayliss
    • , François Bouchy
    • , Claudia Belardi
    • , Edward M. Bryant
    • , Matthew R. Burleigh
    • , Juan Cabrera
    • , Sarah L. Casewell
    • , Alexander Chaushev
    • , Benjamin F. Cooke
    • , Philipp Eigmüller
    • , Anders Erikson
    • , Emma Foxell
    • , Boris T. Gänsicke
    • , Samuel Gill
    • , Edward Gillen
    • , Maximilian N. Günther
    • , Michael R. Goad
    • , Matthew J. Hooton
    • , James A. G. Jackman
    • , Tom Louden
    • , James McCormac
    • , Maximiliano Moyano
    • , Louise D. Nielsen
    • , Don Pollacco
    • , Didier Queloz
    • , Heike Rauer
    • , Liam Raynard
    • , Alexis M. S. Smith
    • , Rosanna H. Tilbrook
    • , Ruth Titz-Weider
    • , Oliver Turner
    • , Stéphane Udry
    • , Simon. R. Walker
    • , Christopher A. Watson
    • , Richard G. West
    • , Enric Palle
    • , Carl Ziegler
    • , Nicholas Law
    •  & Andrew W. Mann
  • Letter |

    The optical follow-up and analysis of two neutron star–black hole merger candidates with the Zwicky Transient Facility did not yield viable counterparts. However, state-of-the-art kilonova models constrain the ejecta properties of these mergers.

    • Shreya Anand
    • , Michael W. Coughlin
    • , Mansi M. Kasliwal
    • , Mattia Bulla
    • , Tomás Ahumada
    • , Ana Sagués Carracedo
    • , Mouza Almualla
    • , Igor Andreoni
    • , Robert Stein
    • , Francois Foucart
    • , Leo P. Singer
    • , Jesper Sollerman
    • , Eric C. Bellm
    • , Bryce Bolin
    • , M. D. Caballero-García
    • , Alberto J. Castro-Tirado
    • , S. Bradley Cenko
    • , Kishalay De
    • , Richard G. Dekany
    • , Dmitry A. Duev
    • , Michael Feeney
    • , Christoffer Fremling
    • , Daniel A. Goldstein
    • , V. Zach Golkhou
    • , Matthew J. Graham
    • , Nidhal Guessoum
    • , Matthew J. Hankins
    • , Youdong Hu
    • , Albert K. H. Kong
    • , Erik C. Kool
    • , S. R. Kulkarni
    • , Harsh Kumar
    • , Russ R. Laher
    • , Frank J. Masci
    • , Przemek Mróz
    • , Samaya Nissanke
    • , Michael Porter
    • , Simeon Reusch
    • , Reed Riddle
    • , Philippe Rosnet
    • , Ben Rusholme
    • , Eugene Serabyn
    • , R. Sánchez-Ramírez
    • , Mickael Rigault
    • , David L. Shupe
    • , Roger Smith
    • , Maayane T. Soumagnac
    • , Richard Walters
    •  & Azamat F. Valeev
  • Letter |

    Three different layers can be distinguished in the first 500 metres of depth beneath the South Pole–Aitken basin on the Moon: a first layer made up by regolith and ejecta material from different craters, followed by a middle unit of mare basalts and finally a >200-m-thick layer of ejecta from the Leibnitz crater.

    • Jinhai Zhang
    • , Bin Zhou
    • , Yangting Lin
    • , Meng-Hua Zhu
    • , Hanjie Song
    • , Zehua Dong
    • , Yunze Gao
    • , Kaichang Di
    • , Wei Yang
    • , Hongyu Lin
    • , Jianfeng Yang
    • , Enhai Liu
    • , Lei Wang
    • , Yi Lin
    • , Chao Li
    • , Zongyu Yue
    • , Zhenxing Yao
    •  & Ziyuan Ouyang
  • Letter |

    The detection of Lyman continuum emission with a high escape fraction from a low-mass clumpy galaxy at z = 1.42, in a redshift range where previously no similar sources were detected, opens up a new window to constrain the shape of the ionization spectrum.

    • Kanak Saha
    • , Shyam N. Tandon
    • , Charlotte Simmonds
    • , Anne Verhamme
    • , Abhishek Paswan
    • , Daniel Schaerer
    • , Michael Rutkowski
    • , Anshuman Borgohain
    • , Bruce Elmegreen
    • , Akio K. Inoue
    • , Francoise Combes
    • , Debra Elmegreen
    •  & Mieke Paalvast
  • Letter |

    Ten years of gamma-ray data reveal emission in the vicinity of the microquasar SS 433 that is co-spatial with an interstellar gas enhancement and varies periodically at the precessional period of SS 433, challenging existing theoretical models.

    • Jian Li
    • , Diego F. Torres
    • , Ruo-Yu Liu
    • , Matthew Kerr
    • , Emma de Oña Wilhelmi
    •  & Yang Su
  • Letter |

    High-resolution gravity data from Dawn’s second extended mission could probe the global and local structure of Ceres’s crust. The results show significant spatial and vertical variations of crustal density and porosity, associated with ice features and ice-related processes driven from the interior, and impacts.

    • R. S. Park
    • , A. S. Konopliv
    • , A. I. Ermakov
    • , J. C. Castillo-Rogez
    • , R. R. Fu
    • , K. H. G. Hughson
    • , T. H. Prettyman
    • , C. A. Raymond
    • , J. E. C. Scully
    • , H. G. Sizemore
    • , M. M. Sori
    • , A. T. Vaughan
    • , G. Mitri
    • , B. E. Schmidt
    •  & C. T. Russell
  • Letter |

    High-resolution data of Ceres’s bright spots (faculae), obtained by Dawn’s second extended mission, suggest the existence of a deep brine-rich reservoir that emerged to the surface through long-lived cryovolcanic activity as a consequence of the impact that created Occator crater.

    • C. A. Raymond
    • , A. I. Ermakov
    • , J. C. Castillo-Rogez
    • , S. Marchi
    • , B. C. Johnson
    • , M. A. Hesse
    • , J. E. C. Scully
    • , D. L. Buczkowski
    • , H. G. Sizemore
    • , P. M. Schenk
    • , A. Nathues
    • , R. S. Park
    • , T. H. Prettyman
    • , L. C. Quick
    • , J. T. Keane
    • , M. D. Rayman
    •  & C. T. Russell
  • Letter |

    Global images of helium and hydrogen emission are used to directly derive the helium abundance out to 2.2R. The helium abundance is shaped by the large-scale coronal magnetic field. Helium is almost completely depleted near the equator in the quiet Sun.

    • John D. Moses
    • , Ester Antonucci
    • , Jeffrey Newmark
    • , Frédéric Auchère
    • , Silvano Fineschi
    • , Marco Romoli
    • , Daniele Telloni
    • , Giuseppe Massone
    • , Luca Zangrilli
    • , Mauro Focardi
    • , Federico Landini
    • , Maurizio Pancrazzi
    • , Guglielmo Rossi
    • , Andrea M. Malvezzi
    • , Dennis Wang
    • , Jean-Christophe Leclec’h
    • , Jean-Pierre Moalic
    • , Frédéric Rouesnel
    • , Lucia Abbo
    • , Aurélien Canou
    • , Nicolas Barbey
    • , Chloé Guennou
    • , John M. Laming
    • , James Lemen
    • , Jean-Pierre Wuelser
    • , John L. Kohl
    •  & Lawrence D. Gardner
  • Letter |

    A large streamer of infalling material joins the dense core with the accretion disk around a young protostar, where the streamer is linked to disk structures. This finding demonstrates the importance of a big-picture viewpoint when studying small-scale accretion features.

    • Jaime E. Pineda
    • , Dominique Segura-Cox
    • , Paola Caselli
    • , Nichol Cunningham
    • , Bo Zhao
    • , Anika Schmiedeke
    • , Maria José Maureira
    •  & Roberto Neri
  • Letter |

    Observations of the X8.2 solar flare, which happened on 2017 September 10, could spatially resolve the distribution of the energetic electrons along the reconnection current sheet. More than 99% of them are concentrated at the bottom of the current sheet, not at the reconnection X point.

    • Bin Chen
    • , Chengcai Shen
    • , Dale E. Gary
    • , Katharine K. Reeves
    • , Gregory D. Fleishman
    • , Sijie Yu
    • , Fan Guo
    • , Säm Krucker
    • , Jun Lin
    • , Gelu M. Nita
    •  & Xiangliang Kong
  • Letter |

    Stellar intensity interferometry (SII) is undergoing a revival. Here, data from the four 12 m optical reflectors of the VERITAS array are correlated post facto to determine the angular diameter of two stars to a high precision, laying the groundwork for SII at future large Cherenkov arrays.

    • A. U. Abeysekara
    • , W. Benbow
    • , A. Brill
    • , J. H. Buckley
    • , J. L. Christiansen
    • , A. J. Chromey
    • , M. K. Daniel
    • , J. Davis
    • , A. Falcone
    • , Q. Feng
    • , J. P. Finley
    • , L. Fortson
    • , A. Furniss
    • , A. Gent
    • , C. Giuri
    • , O. Gueta
    • , D. Hanna
    • , T. Hassan
    • , O. Hervet
    • , J. Holder
    • , G. Hughes
    • , T. B. Humensky
    • , P. Kaaret
    • , M. Kertzman
    • , D. Kieda
    • , F. Krennrich
    • , S. Kumar
    • , T. LeBohec
    • , T. T. Y. Lin
    • , M. Lundy
    • , G. Maier
    • , N. Matthews
    • , P. Moriarty
    • , R. Mukherjee
    • , M. Nievas-Rosillo
    • , S. O’Brien
    • , R. A. Ong
    • , A. N. Otte
    • , K. Pfrang
    • , M. Pohl
    • , R. R. Prado
    • , E. Pueschel
    • , J. Quinn
    • , K. Ragan
    • , P. T. Reynolds
    • , D. Ribeiro
    • , G. T. Richards
    • , E. Roache
    • , J. L. Ryan
    • , M. Santander
    • , G. H. Sembroski
    • , S. P. Wakely
    • , A. Weinstein
    • , P. Wilcox
    • , D. A. Williams
    •  & T. J. Williamson
  • Letter |

    Conditions in an accretion burst around a high-mass young stellar object (HMYSO) were sufficient to pump two species previously not known to maser. HDO and HNCO were found to trace spiral-arm features in the accretion flow onto the HMYSO.

    • Xi Chen
    • , Andrej M. Sobolev
    • , Zhi-Yuan Ren
    • , Sergey Parfenov
    • , Shari L. Breen
    • , Simon P. Ellingsen
    • , Zhi-Qiang Shen
    • , Bin Li
    • , Gordon C. MacLeod
    • , Willem Baan
    • , Crystal Brogan
    • , Tomoya Hirota
    • , Todd R. Hunter
    • , Hendrik Linz
    • , Karl Menten
    • , Koichiro Sugiyama
    • , Bringfried Stecklum
    • , Yan Gong
    •  & Xingwu Zheng
  • Letter |

    Low-mass stars are expected to destroy their lithium content as they evolve, but this study of stars in the red clump evolutionary stage shows that their lithium abundance is on average forty times greater than at the end of the previous stage, something not predicted by theory.

    • Yerra Bharat Kumar
    • , Bacham E. Reddy
    • , Simon W. Campbell
    • , Sunayana Maben
    • , Gang Zhao
    •  & Yuan-Sen Ting
  • Letter |

    Statistical analysis of velocity fluctuations in the interstellar medium (ISM) of the Milky Way and NGC 4321 show that the motion of molecular gas over scales ranging from 0.1 to 1,000 pc is similar, and consistent with that generated by a combination of gravity and turbulence. ISM structure at one scale is therefore linked to structure at other scales.

    • Jonathan D. Henshaw
    • , J. M. Diederik Kruijssen
    • , Steven N. Longmore
    • , Manuel Riener
    • , Adam K. Leroy
    • , Erik Rosolowsky
    • , Adam Ginsburg
    • , Cara Battersby
    • , Mélanie Chevance
    • , Sharon E. Meidt
    • , Simon C. O. Glover
    • , Annie Hughes
    • , Jouni Kainulainen
    • , Ralf S. Klessen
    • , Eva Schinnerer
    • , Andreas Schruba
    • , Henrik Beuther
    • , Frank Bigiel
    • , Guillermo A. Blanc
    • , Eric Emsellem
    • , Thomas Henning
    • , Cynthia N. Herrera
    • , Eric W. Koch
    • , Jérôme Pety
    • , Sarah E. Ragan
    •  & Jiayi Sun
  • Letter |

    The oxygen emission at 557.7 nm, responsible for the green colour of auroras on Earth, is present in two layers at 80 and 120 km altitude on the dayside atmosphere of Mars. Simultaneous observations of the oxygen both in this visible line and in the ultraviolet could also constrain the elusive visible/ultraviolet intensity ratio of the auroral emission to a value of 16.5.

    • J.-C. Gérard
    • , S. Aoki
    • , Y. Willame
    • , L. Gkouvelis
    • , C. Depiesse
    • , I. R. Thomas
    • , B. Ristic
    • , A. C. Vandaele
    • , F. Daerden
    • , B. Hubert
    • , J. Mason
    • , M. R. Patel
    • , J.-J. López-Moreno
    • , G. Bellucci
    • , M. A. López-Valverde
    •  & B. Beeckman
  • Letter |

    Titan is migrating away from Saturn on a much shorter timescale than expected, lending support to the resonance-locking tidal theory. This result motivates a revision of the evolutionary history of Saturn’s moon system and may be relevant to other giant planets.

    • Valéry Lainey
    • , Luis Gomez Casajus
    • , Jim Fuller
    • , Marco Zannoni
    • , Paolo Tortora
    • , Nicholas Cooper
    • , Carl Murray
    • , Dario Modenini
    • , Ryan S. Park
    • , Vincent Robert
    •  & Qingfeng Zhang
  • Letter |

    A detailed microphysical model shows that there are two distinct regimes in the aerosol composition of exoplanetary atmospheres: silicates dominate at atmospheric temperatures above 950 K, whereas hydrocarbons prevail for temperatures below 950 K.

    • Peter Gao
    • , Daniel P. Thorngren
    • , Graham K. H. Lee
    • , Jonathan J. Fortney
    • , Caroline V. Morley
    • , Hannah R. Wakeford
    • , Diana K. Powell
    • , Kevin B. Stevenson
    •  & Xi Zhang
  • Letter |

    A ring galaxy is found at a look-back time of 10.8 Gyr. The diffuse stellar light outside the star-forming ring, the ring’s radial velocity and a nearby intruder galaxy indicate that this is a collisional ring galaxy.

    • Tiantian Yuan
    • , Ahmed Elagali
    • , Ivo Labbé
    • , Glenn G. Kacprzak
    • , Claudia del P. Lagos
    • , Leo Y. Alcorn
    • , Jonathan H. Cohn
    • , Kim-Vy H. Tran
    • , Karl Glazebrook
    • , Brent A. Groves
    • , Kenneth C. Freeman
    • , Lee R. Spitler
    • , Caroline M. S. Straatman
    • , Deanne B. Fisher
    •  & Sarah M. Sweet
  • Letter |

    A map of the stability of brines on Mars, obtained by combining thermodynamic and climate modelling, shows that some brines can stay liquid for longer than previously thought, particularly at high northern latitudes. However, they are not habitable to known terrestrial life, and can be explored without risk of biological contamination from Earth.

    • Edgard G. Rivera-Valentín
    • , Vincent F. Chevrier
    • , Alejandro Soto
    •  & Germán Martínez
  • Letter |

    A soft X-ray polarimetry capability has been missing from astronomy since the late 1970s. Here a CubeSat polarimeter named PolarLight has detected the Crab nebula and pulsar in the soft X-ray band, measuring their polarized emission. PolarLight observed a pulsar glitch, with an associated polarization change.

    • Hua Feng
    • , Hong Li
    • , Xiangyun Long
    • , Ronaldo Bellazzini
    • , Enrico Costa
    • , Qiong Wu
    • , Jiahui Huang
    • , Weichun Jiang
    • , Massimo Minuti
    • , Weihua Wang
    • , Renxin Xu
    • , Dongxin Yang
    • , Luca Baldini
    • , Saverio Citraro
    • , Hikmat Nasimi
    • , Paolo Soffitta
    • , Fabio Muleri
    • , Aera Jung
    • , Jiandong Yu
    • , Ge Jin
    • , Ming Zeng
    • , Peng An
    • , Alessandro Brez
    • , Luca Latronico
    • , Carmelo Sgro
    • , Gloria Spandre
    •  & Michele Pinchera
  • Letter |

    High-resolution radiation-hydrodynamic simulations of galaxy clusters show that extended cold gas filaments can form in the centre of clusters through the combination of radiative cooling and ram pressure from feedback driven by the central active galactic nucleus.

    • Yu Qiu
    • , Tamara Bogdanović
    • , Yuan Li
    • , Michael McDonald
    •  & Brian R. McNamara
  • Letter |

    Hubble Space Telescope data show that interstellar comet 2I/Borisov has an unusually high CO/H2O ratio—higher than any other comet that has been seen in the inner regions of our Solar System. This allows us to constrain the nature and location of the circumstellar region from which 2I/Borisov originated.

    • D. Bodewits
    • , J. W. Noonan
    • , P. D. Feldman
    • , M. T. Bannister
    • , D. Farnocchia
    • , W. M. Harris
    • , J.-Y. Li
    • , K. E. Mandt
    • , J. Wm. Parker
    •  & Z.-X. Xing
  • Letter |

    Interstellar comet Borisov has thus far looked very much like a Solar System comet in terms of its volatile content, but with new data from ALMA that show robust detections of CO and HCN, it is clear that Borisov is rich in CO, helping to pinpoint its origin.

    • M. A. Cordiner
    • , S. N. Milam
    • , N. Biver
    • , D. Bockelée-Morvan
    • , N. X. Roth
    • , E. A. Bergin
    • , E. Jehin
    • , A. J. Remijan
    • , S. B. Charnley
    • , M. J. Mumma
    • , J. Boissier
    • , J. Crovisier
    • , L. Paganini
    • , Y.-J. Kuan
    •  & D. C. Lis
  • Letter |

    Tidal fragmentation of a planetary body that orbited too close to its star can explain all the peculiar characteristics of the interstellar visitor ‘Oumuamua, a formation model shows. Kilometre-sized comets, super-Earths and sub-Neptune exoplanets around subsolar stars or white dwarfs are the most probable parent bodies.

    • Yun Zhang
    •  & Douglas N. C. Lin
  • Letter |

    A recent supernova event, SN2016aps, must have involved an extremely energetic explosion and a very massive star, potentially indicating a pair-instability supernova or pulsational pair-instability supernova mechanism.

    • Matt Nicholl
    • , Peter K. Blanchard
    • , Edo Berger
    • , Ryan Chornock
    • , Raffaella Margutti
    • , Sebastian Gomez
    • , Ragnhild Lunnan
    • , Adam A. Miller
    • , Wen-fai Fong
    • , Giacomo Terreran
    • , Alejandro Vigna-Gómez
    • , Kornpob Bhirombhakdi
    • , Allyson Bieryla
    • , Pete Challis
    • , Russ R. Laher
    • , Frank J. Masci
    •  & Kerry Paterson
  • Letter |

    Simultaneous optical and gamma-ray observations of nova V906 Carinae reveal correlated flares in both wavelength ranges that can be linked to shocks in the nova ejecta. Weak X-ray emission suggests that the shocks are deeply embedded, but they contribute substantially to the luminosity of the nova.

    • Elias Aydi
    • , Kirill V . Sokolovsky
    • , Laura Chomiuk
    • , Elad Steinberg
    • , Kwan Lok Li
    • , Indrek Vurm
    • , Brian D. Metzger
    • , Jay Strader
    • , Koji Mukai
    • , Ondřej Pejcha
    • , Ken J. Shen
    • , Gregg A. Wade
    • , Rainer Kuschnig
    • , Anthony F. J. Moffat
    • , Herbert Pablo
    • , Andrzej Pigulski
    • , Adam Popowicz
    • , Werner Weiss
    • , Konstanze Zwintz
    • , Luca Izzo
    • , Karen R. Pollard
    • , Gerald Handler
    • , Stuart D. Ryder
    • , Miroslav D. Filipović
    • , Rami Z. E. Alsaberi
    • , Perica Manojlović
    • , Raimundo Lopes de Oliveira
    • , Frederick M. Walter
    • , Patrick J. Vallely
    • , David A. H. Buckley
    • , Michael J. I. Brown
    • , Eamonn J. Harvey
    • , Adam Kawash
    • , Alexei Kniazev
    • , Christopher S. Kochanek
    • , Justin Linford
    • , Joanna Mikolajewska
    • , Paolo Molaro
    • , Marina Orio
    • , Kim L. Page
    • , Benjamin J. Shappee
    •  & Jennifer L. Sokoloski
  • Letter |

    The complete latitudinal coverage of Saturn’s thermospheric temperatures from Cassini Grand Finale data shows a more uniform spatial behaviour than model predictions, indicating an efficient redistribution of auroral energy from the poles towards the equator that could contribute to solving the giant planet’s energy crisis puzzle.

    • Z. Brown
    • , T. Koskinen
    • , I. Müller-Wodarg
    • , R. West
    • , A. Jouchoux
    •  & L. Esposito
  • Letter |

    The exoplanet atmospheres we study may not be primary atmospheres. Models show that the accretion of gas late in a planetary system’s formation may completely replace the primary atmospheres of terrestrial planets. These secondary atmospheres are likely to have high metallicities and high C/O ratios.

    • Quentin Kral
    • , Jeanne Davoult
    •  & Benjamin Charnay
  • Letter |

    It is difficult to reproduce the formation and composition of the moons of Uranus with a standard giant-impact model. Observations and modelling can be reconciled if the evolution of the water content in the disk, which is assumed to be vaporized and thus mostly accretes onto the planet before recondensation, is considered.

    • Shigeru Ida
    • , Shoji Ueta
    • , Takanori Sasaki
    •  & Yuya Ishizawa
  • Letter |

    Cataclysmic variables—a binary pairing of a white dwarf and a hydrogen-rich donor star—experience mass transfer and other complex interactions. This numerical simulation by Hillman et al. models in particular the feedback between the stellar pair, and succeeds in reproducing many of the observed characteristics of cataclysmic variables.

    • Yael Hillman
    • , Michael M. Shara
    • , Dina Prialnik
    •  & Attay Kovetz
  • Letter |

    The abundances of isotopes in presolar grains are presumed to reflect their nucleosynthetic generation in stars. However, here Robert et al. report experimentally detected evidence of mass-independent fractionation of titanium, implying that titanium isotopic abundances in presolar grains may not be as representative as once thought.

    • François Robert
    • , Romain Tartèse
    • , Guillaume Lombardi
    • , Peter Reinhardt
    • , Mathieu Roskosz
    • , Béatrice Doisneau
    • , Zhengbin Deng
    •  & Marc Chaussidon
  • Letter |

    The gas kinematics within a Lyman-α blob show clear evidence of infall, consistent with the release of gravitational accretion energy as cold streams radiate Lyman-α photons. These cold streams are apparently responsible for feeding central galaxies.

    • Yiping Ao
    • , Zheng Zheng
    • , Christian Henkel
    • , Shiyu Nie
    • , Alexandre Beelen
    • , Renyue Cen
    • , Mark Dijkstra
    • , Paul J. Francis
    • , James E. Geach
    • , Kotaro Kohno
    • , Matthew D. Lehnert
    • , Karl M. Menten
    • , Junzhi Wang
    •  & Axel Weiss
  • Letter |

    Uniform analysis of both main-sequence and evolved, post-main-sequence stars shows that a common, turbulence-dependent, dynamo mechanism operates throughout these stages of stellar evolution.

    • Jyri J. Lehtinen
    • , Federico Spada
    • , Maarit J. Käpylä
    • , Nigul Olspert
    •  & Petri J. Käpylä
  • Letter |

    2M1510 is an approximately 45-million-year-old triple system of brown dwarfs, two of which form a close binary in a 20-day orbit and have almost the same mass (3.82% and 3.75% of the mass of the Sun, respectively). Their physical parameters are in good agreement with evolutionary models except for luminosity, suggesting that we might be underestimating the masses of brown dwarfs and massive exoplanets by about 30%.

    • Amaury H. M. J. Triaud
    • , Adam J. Burgasser
    • , Artem Burdanov
    • , Vedad Kunovac Hodžić
    • , Roi Alonso
    • , Daniella Bardalez Gagliuffi
    • , Laetitia Delrez
    • , Brice-Olivier Demory
    • , Julien de Wit
    • , Elsa Ducrot
    • , Frederic V. Hessman
    • , Tim-Oliver Husser
    • , Emmanuël Jehin
    • , Peter P. Pedersen
    • , Didier Queloz
    • , James McCormac
    • , Catriona Murray
    • , Daniel Sebastian
    • , Samantha Thompson
    • , Valérie Van Grootel
    •  & Michaël Gillon
  • Letter |

    A massive white dwarf (WD) with unusually low hydrogen and helium abundances, undetectable oxygen and high C/H poses a challenge to single-star evolution models. However, this object fits with expectations of a WD–WD merger product.

    • M. A. Hollands
    • , P.-E. Tremblay
    • , B. T. Gänsicke
    • , M. E. Camisassa
    • , D. Koester
    • , A. Aungwerojwit
    • , P. Chote
    • , A. H. Córsico
    • , V. S. Dhillon
    • , N. P. Gentile-Fusillo
    • , M. J. Hoskin
    • , P. Izquierdo
    • , T. R. Marsh
    •  & D. Steeghs
  • Letter |

    Our Galaxy’s disk is warped, and that warp is dynamic. Here, Poggio et al. measure the rate of precession of the Galaxy’s warp using a large sample of giant stars. Rather than primordial, the rate of precession indicates that the Milky Way acquired its warp during a recent or even ongoing encounter with another galaxy.

    • E. Poggio
    • , R. Drimmel
    • , R. Andrae
    • , C. A. L. Bailer-Jones
    • , M. Fouesneau
    • , M. G. Lattanzi
    • , R. L. Smart
    •  & A. Spagna
  • Letter |

    Low-frequency radio emission from a normally quiescent M dwarf star suggests a radio aurora generated by the interaction between the stellar corona and an undetected Earth-sized planet.

    • H. K. Vedantham
    • , J. R. Callingham
    • , T. W. Shimwell
    • , C. Tasse
    • , B. J. S. Pope
    • , M. Bedell
    • , I. Snellen
    • , P. Best
    • , M. J. Hardcastle
    • , M. Haverkorn
    • , A. Mechev
    • , S. P. O’Sullivan
    • , H. J. A. Röttgering
    •  & G. J. White
  • Letter |

    Using two independent laser frequency combs to calibrate an astronomical spectrometer, researchers demonstrate a stability of ~1 cm s–1, which is required for detecting low-mass rocky exoplanets around Sun-like stars.

    • Rafael A. Probst
    • , Dinko Milaković
    • , Borja Toledo-Padrón
    • , Gaspare Lo Curto
    • , Gerardo Avila
    • , Anna Brucalassi
    • , Bruno L. Canto Martins
    • , Izan de Castro Leão
    • , Massimiliano Esposito
    • , Jonay I. González Hernández
    • , Frank Grupp
    • , Theodor W. Hänsch
    • , Hanna Kellermann
    • , Florian Kerber
    • , Olaf Mandel
    • , Antonio Manescau
    • , Eszter Pozna
    • , Rafael Rebolo
    • , José R. de Medeiros
    • , Tilo Steinmetz
    • , Alejandro Suárez Mascareño
    • , Thomas Udem
    • , Josefina Urrutia
    • , Yuanjie Wu
    • , Luca Pasquini
    •  & Ronald Holzwarth
  • Letter |

    High-resolution observations of the third largest asteroid, (2) Pallas, from SPHERE unveil a heavily cratered surface, probably due to Pallas’s inclined and eccentric orbit, a density almost equal to carbonaceous chondrites and hint at surficial salt-enriched spots.

    • Michaël Marsset
    • , Miroslav Brož
    • , Pierre Vernazza
    • , Alexis Drouard
    • , Julie Castillo-Rogez
    • , Josef Hanuš
    • , Matti Viikinkoski
    • , Nicolas Rambaux
    • , Benoît Carry
    • , Laurent Jorda
    • , Pavel Ševeček
    • , Mirel Birlan
    • , Franck Marchis
    • , Edyta Podlewska-Gaca
    • , Erik Asphaug
    • , Przemyslaw Bartczak
    • , Jérôme Berthier
    • , Fabrice Cipriani
    • , François Colas
    • , Grzegorz Dudziński
    • , Christophe Dumas
    • , Josef Ďurech
    • , Marin Ferrais
    • , Romain Fétick
    • , Thierry Fusco
    • , Emmanuel Jehin
    • , Mikko Kaasalainen
    • , Agnieszka Kryszczynska
    • , Philippe Lamy
    • , Hervé Le Coroller
    • , Anna Marciniak
    • , Tadeusz Michalowski
    • , Patrick Michel
    • , Derek C. Richardson
    • , Toni Santana-Ros
    • , Paolo Tanga
    • , Frédéric Vachier
    • , Arthur Vigan
    • , Olivier Witasse
    •  & Bin Yang
  • Letter |

    Sporadic E layers are unpredictable terrestrial ionospheric phenomena that can perturb telecommunication. Plasma features akin to sporadic E layers and their opposite (sporadic E rifts), never observed on Earth, were detected in the ionosphere of Mars from MAVEN data. In contrast to those observed on Earth, they are long lived and form at predictable locations.

    • Glyn A. Collinson
    • , James McFadden
    • , Joseph Grebowsky
    • , David Mitchell
    • , Rob Lillis
    • , Paul Withers
    • , Marissa F. Vogt
    • , Mehdi Benna
    • , Jared Espley
    •  & Bruce Jakosky
  • Letter |

    Keen observations of the Cassiopeia A supernova remnant have identified a circumstellar clump that lies outside the supernova shock front. This unprocessed material from the supernova progenitor contains iron in the gas phase, and is consistent with an origin within a blue supergiant star.

    • Bon-Chul Koo
    • , Hyun-Jeong Kim
    • , Heeyoung Oh
    • , John C. Raymond
    • , Sung-Chul Yoon
    • , Yong-Hyun Lee
    •  & Daniel T. Jaffe
  • Letter |

    Relativistic modelling of long X-ray observations of a highly variable active galaxy reveals that the height of its X-ray corona increases with increasing luminosity. X-ray reverberation is shown to be a powerful technique to measure black hole masses.

    • William N. Alston
    • , Andrew C. Fabian
    • , Erin Kara
    • , Michael L. Parker
    • , Michal Dovciak
    • , Ciro Pinto
    • , Jiachen Jiang
    • , Matthew J. Middleton
    • , Giovanni Miniutti
    • , Dominic J. Walton
    • , Dan R. Wilkins
    • , Douglas J. K. Buisson
    • , Maria D. Caballero-Garcia
    • , Edward M. Cackett
    • , Barbara De Marco
    • , Luigi C. Gallo
    • , Anne M. Lohfink
    • , Chris S. Reynolds
    • , Phil Uttley
    • , Andrew J. Young
    •  & Abderahmen Zogbhi