Letters

Outbursts from accreting pulsars encode much information on mass accretion in X-ray binary systems. Measuring optical as well as X-ray pulsations can constrain models and, indeed, point to particle acceleration taking place during accretion.

Tidal-evolution modelling, combined with new geophysical constraints of Mars and viscoelastic laboratory measurements, suggests that the two Martian moons have a common progenitor that was disrupted between 1 and 2.7 billion years ago.

A recent association of a tidal disruption event with neutrino emission can be explained by an expanding cocoon from a relativistic jet providing an external target of backscattered X-rays for the production of neutrinos via proton–photon interactions.

In April 2020, the Konus-Wind instrument registered two X-ray bursts temporally coincident with two radio bursts from the Galactic magnetar SGR 1935+2154. The unusual spectral hardness of the X-ray bursts may be an indicator of fast-radio-burst-like radio emission from magnetars.

Insight-HXMT detected a double-peaked X-ray burst from Galactic magnetar SGR J1935+2154, consistent with two fast radio bursts (FRBs) observed from the same object within seconds. This coincidence suggests a common physical origin, and gives insight into the mechanism behind the origin of FRBs.

Detections of lithium (and in one case, potassium) in the atmospheres of four old white dwarfs suggest that they have accreted fragments of planets; specifically, planetary crusts. One white dwarf evolved from an intermediate-mass progenitor, indicating that rocky planets form even around short-lived B-type stars.

The formation mechanism of the most common type of planet in the Galaxy, those with masses between those of the Earth and Neptune, is far from clear. However, simulations of disk fragmentation presented here, which incorporate a spiral-driven dynamo, produce protoplanets of the right mass and longevity.

Stars in the Tucana II ultrafaint dwarf galaxy observed out to nine half-light radii reveal the presence of an extended dark matter halo with a total mass of >10⁷ solar masses, consistent with a generalized Navarro–Frenk–White density profile and suggestive of past strong bursty feedback or an early galactic merger.

Sticking coefficients quantify the readiness of gas molecules to freeze onto the surface of dust grains. Here, laboratory measurements of the sticking coefficients of water and carbon dioxide onto realistic bare and icy dust grain analogues provide key data for the study of snowlines in protoplanetary disks, for example.

Three-dimensional hydrodynamic simulations show that head-on galaxy collisions can suppress black hole fuelling by stripping the torus-shaped gas surrounding the massive black hole. Galaxy collisions could therefore either switch off or turn on nuclear activity, depending on the collision orbit.

The protocluster LAGER-z7OD1 is discovered at a redshift of 6.93, identified by an overdensity of 6 times the average galaxy density and 16 spectroscopically confirmed members. It shows an elongated shape, indicative of a past merger, and its intergalactic medium is almost fully ionized.

Studies of iron meteorites show that volatile nitrogen originated in three isotopically distinct reservoirs in the early Solar System: the nebular gas, sampled by the Sun and Jupiter, and two others related to organic molecules and dust in the inner and outer Solar System, from which growing protoplanets incorporated nitrogen.

Saturn crossed the orbital resonance that tilted it to its present obliquity of 26.7° only about 1 billion years ago, affected by the fast migration of Titan. The impact of satellite migration on the evolution of giant planet obliquities may be a general phenomenon that could also be relevant for Jupiter and exoplanetary systems.

Gigaelectronvolt emission from a magnetar giant flare is discovered by the Fermi Gamma-ray Space Telescope, between 19 s and 284 s after the initial detection of a signal in the megaelectronvolt energy band, potentially generated by an ultra-relativistic outflow far from the stellar magnetosphere.

A high-resolution simulation of interstellar turbulence determines the position and width of the transition from supersonic to subsonic turbulence, providing quantitative input for models of filament structure and star formation in molecular clouds.

Hayabusa2 created an artificial crater on Ryugu to analyse the subsurficial material of the asteroid. Results show that the subsurface is more hydrated than the surface. It experienced alteration processes that can be traced back to Ryugu’s parent body.

The Almahata Sitta 202 meteorite fragment hosts evidence of aqueous alteration at intermediate pressures and temperatures, indicative of a hitherto unknown Ceres-sized parent body. Such intermediate conditions, also seen in the Allende meteorite, might have been more common than our biased meteorite collection indicates.

The detection of three ultraviolet emission lines from GN-z11 can be interpreted as the [C iii] λ1907, C iii] λ1909 doublet and O iii] λ1666 at z = 10.957 ± 0.001, confirming GN-z11 as the most distant galaxy known to date and revealing the properties of its dense ionized gas.

A peculiar near-infrared transient with an observed duration shorter than 245 s, coincident with the luminous star-forming galaxy GN-z11 at z ≈ 11, might have arisen from a rest-frame ultraviolet flash associated with a long gamma-ray burst in GN-z11.

Solar imaging and spectral data indicate that impulsive heating through magnetic reconnection in transition region loops is responsible for observed transient brightenings, consistent with ion cyclotron turbulence due to strong currents at the reconnection sites.