Letters

The presence of a scalar charge around a small compact object during its final inspiral into a supermassive black hole could be detected by LISA, providing a way to test deviations from general relativity and the existence of new fields in nature.

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.

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.

The hydrogen isotopic composition of the oldest Solar System rocks demonstrates that a gaseous reservoir of terrestrial isotopic composition existed as early as the onset of Solar System formation and coexisted with the solar gas.

The rich transmission spectrum of exoplanet WASP-189 b reveals its dynamical atmosphere with a three-dimensional thermochemical stratification, requiring the unification of dynamical, thermal and chemical models for its study.

Supra-arcade downflows are dark finger-like structures associated with solar flares. Simulations now suggest that these plasma downflows form within a turbulent region that may control turbulent flows, electron currents and shockwaves.

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.

Massive black holes that are produced dynamically by black hole mergers are thought to involve eccentric orbits, whose imprint may remain in the gravitational waveform detected by the LIGO/Virgo Collaboration.

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.

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.

Through an analysis of broad absorption lines in a range of quasars, quasar outflows are shown to have a negative global feedback effect on star formation, demonstrated by the recovery of star formation rates after the outflows disappear.

A Bayesian imaging method for reconstructing radio emission in spatial, temporal and spectral dimensions confirms the structures on the time-varying emission ring of M87* observed by the Event Horizon Telescope, and identifies additional features.

Previously unresolved radio features of nearby Centaurus A reveal transition regions for both the feeding of this active galaxy and the feedback mechanism for recycling energy back into the surrounding medium.

A population of free-floating planets in Upper Scorpius that is larger than that predicted by core-collapse models suggests that the ejection of planets due to dynamical interactions early in the lifetime of a forming planetary system is more common than prevoiusly thought.

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.

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.

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.

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.

The authors report the linear correlation of X-ray and Hα surface brightnesses in the material stripped from a galaxy, providing evidence for the mixing of galactic interstellar and hot intra-cluster medium as the origin of the multi-phase stripped tails observed previously.

A high-frequency quasiperiodic oscillation in the soft X-rays from unusual transient AT2018cow points towards the presence of a compact object in the remnant: either a neutron star with spin period of 4 ms or a low-mass black hole.