Letters

An energetic eruptive filament on EK Draconis most probably launched a coronal mass ejection with a mass ten times larger than the largest solar coronal mass ejection. Studying such ejections provides insight into stellar angular momentum loss and the habitability of orbiting planets.

The Zhurong rover has explored its landing site in Utopia Planitia, Mars, and is travelling south towards the highland–lowland boundary, focusing initially on the composition and physical properties of the rocks along the way.

The authors report time-series interferometric observations of a microlensing event from the ground. The lens images rotate during the series, giving the direction of motion of the lens and a very accurate Einstein ring radius. The lens is a 1.1-solar mass object at a distance of 5–6 kpc.

The 20-million-year-old, solar-type star V1298 Tau hosts a multiplanet system. The two outermost planets, gas giants with masses of 0.64 and 1.16 Jupiter masses, respectively, defy current formation models as their mass–radius relationship should be reached much later in the stages of planetary evolution.

The resonant chain of the TRAPPIST-1 planets is dynamically fragile, as small perturbations during its lifetime would have disrupted it. N-body simulations show that the system could not have interacted with more than 0.05 Earth masses of material after its formation. Thus, any water in the planets must come from the planets’ original accretion.

The Chang’e-4 rover observed a small crater formed less than one million years ago, finding glassy materials with spectral characteristics similar to those of carbonaceous chondrites that are identified as remnants of the original impactor that have not yet been affected by weathering processes.

The detection of the HF molecule in a lensed galaxy at z = 4.4 suggests a rapid chemical enrichment. Wolf–Rayet stars are the most likely providers of the fluorine.

General relativistic magnetohydrodynamic simulations with general relativistic radiative transfer reproduce remarkably well the broadband spectrum and morphology of the innermost jet of M87, allowing some first rough constraints on the spin of M87*.

As the Perseverance rover landed on the Martian surface, the sensors on NASA’s InSight Mars lander picked up no seismic or acoustic waves. This non-detection provides information on the crust and atmosphere of Mars.

A population study of near-infrared spectra of 19 hot giant planets shows a correlation between the strength of the 1.4 μm water band and temperature, which is broadly regulated by irradiation. However, the observed scatter around the mean is indicative of the effect of individual planetary formation pathways on the composition.

From its optical light curve, the white dwarf in the binary system TW Pictoris appears to be switching between two different intensities of accretion on timescales of hours. This behaviour is reminiscent of that seen in transitional millisecond pulsars, where the switching occurs several times a minute.

Globular cluster NGC 2005 in the Large Magellanic Cloud (LMC) bears the elemental hallmarks of being an accreted object: a surviving fragment of a galaxy that fell into the LMC long enough ago to have erased any dynamical signature of accretion.

LOFAR observations of a galaxy group reveal multiple generations of cosmic-ray bubbles. The bubble buoyancy power offsets the radiative cooling of the intragroup medium, while magnetic fields prevent mixing between the bubbles and the external medium.

While pulsar timing observations are currently unable to distinguish a binary black hole astrophysical foreground from a cosmological background, integrated bounds on the ultra-low-frequency gravitational wave spectrum from other cosmological probes may help to break this degeneracy.

The authors present 19 detections of coherent low-frequency radio emission from M dwarfs using the Low Frequency Array. The sample includes both chromospherically active and quiescent stars, but radio luminosities are independent of coronal and chromospheric activity indicators.

Basalt samples from the Moon gathered during the Apollo 17 mission hold information on the lunar magnetic field as it was 3.7 billion years ago. Its mean intensity was ~50 μT and its inclination 34 ± 10°. Such results suggest that the lunar dynamo was active at the time and was axially aligned and dipolar.

[C ii] 158 μm emission associated with a strong low-ionization absorber at z = 5.978 indicates a dark matter halo mass of around 4 × 10¹¹ solar masses, one to two orders of magnitude more massive than typical values predicted from cosmological simulations.

A high-resolution calculation reproducing solar-like differential rotation shows that the strong magnetic field generated by a small-scale dynamo has a substantial impact on thermal convection and is a key step in understanding the 11 yr solar cycle.

The discovery of a multiply imaged, probably of type Ia, supernova in a galaxy at redshift 1.95 enables a time-delay measurement with an uncertainty of <1%. The prediction that a new image will appear in the year 2037 ± 2 allows the use of this system as a cosmological probe.

Cosmological hydrodynamical simulations of the ΛCDM Universe show that isolated quenched ultra-diffuse galaxies are formed as backsplash galaxies that were once satellites of another galactic group or cluster halo but are today a few megaparsecs away from them.