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In situ measurements from the Rosetta spacecraft reveal the presence of atomic emissions close to comet 67P’s nucleus. Such emissions are due to dissociative excitation of molecules by the interaction with the solar wind, identifying them as a form of aurora.

dust particles at comet 67P/Churyumov–Gerasimenko confirm that the particles are aggregates of smaller, elongated grains even at the smallest sizes examined.

Observations of water ice on the surface of comet 67P/Churyumov–Gerasimenko show the ice appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity and leading to cycling modification of the ice abundance on the surface.

Using infrared wavelengths, micrometre-sized water-ice grains have been identified on the nucleus (which is mostly coated in a dark material) of comet 67P/Churyumov–Gerasimenko.

Using James Webb Space Telescope observations, spectroscopic identification of a coma of water vapour but no significant CO₂ gas coma is found for the main-belt comet 238P/Read, indicating water–ice sublimation.

The ‘onion-like’ stratification of the two lobes of the comet 67P/Churyumov–Gerasimenko reveals that its unusual shape is the result of a gentle collision merging two kilometre-sized objects in the early stages of the Solar System.

Detailed mapping of the distribution of water and semiheavy water in the coma of Halley-type comet 12P implies a D/H ratio that is consistent with that of Earth’s water, indicating a common heritage.

The shape and internal structure of bilobate comet 67P is controlled by shear deformation inducing mechanically driven erosion along shear fracture networks, according to a 3D analysis of images from the Rosetta mission.

The hydrogen, carbon and nitrogen isotopic compositions of ultra-carbonaceous Antarctic micrometeorites reveal that they are possibly linked with N-bearing volatile species, including primordial N₂, condensed on the coldest objects of the Solar System.

JWST/NIRSpec spectra are used to analyse the surfaces of Centaurs, revealing two main compositions: those with refractory materials and water ice and those rich in carbon-based materials. Strong surface weathering due to thermal processing may be responsible.

The size and spatial distribution of pits on comet 67P/Churyumov–Gerasimenko, which are active and probably created by a sinkhole process, imply that large heterogeneities exist in the physical, structural or compositional properties of the first few hundred metres below the current cometary surface.

Images of 67P's nucleus from the Rosetta spacecraft, together with numerical simulations, show that the jet-like features of cometary comae can be produced by diffuse activity focused by the nucleus topography as well as non-uniform insolation over the surface.

A new analysis of Rosetta mass spectra reveals an ensemble of complex organic molecules with striking similarities to other organic reservoirs in the Solar System, including Saturn’s ring rain material, pointing at a likely joint prestellar history.

The MASCOT lander observed a boulder on the surface of asteroid Ryugu up close. The boulder’s low thermal inertia is closer to fine regolith or comets rather than stony boulders, indicating high porosity and low tensile strength. Orbit measurements confirm that Ryugu’s surface is covered with similar boulders.

Rocks and dust from the asteroid Bennu contain some of the molecular building blocks of life on Earth, such as amino acids and nucleobases. They also carry ammonia that formed billions of years ago in cold, distant regions of our Solar System.

Here, authors study boulders’ fractures on S-type asteroid, Dimorphos, and show that their size-frequency distribution and orientation are consistent with formation through thermal fatigue. Such fractures seem to propagate horizontally much faster (~kyr) than normal to the boulder’s surface (~Myr).

Planetary Defense efforts rely on estimates of asteroids’ mechanical properties, which are difficult to obtain accurately from Earth. Here, authors compare images from space missions to the rubble-pile asteroids Dimorphos, Itokawa, Ryugu, and Bennu and study such properties through boulders on their surface.

Fractures on the asteroid Bennu imaged by the OSIRIS-REx spacecraft are consistent with cracking induced by diurnal temperature variations over geologically rapid timescales.

The asteroid Ryugu experienced aqueous alteration under changing temperature and redox conditions, according to an isotopic analysis of secondary calcite and dolomite grains in samples from Ryugu obtained by the Hayabusa2 spacecraft.

The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H₂S.

Three-body dissociation of water, producing one oxygen and two hydrogen atoms, has been difficult to investigate due to the lack of intense vacuum ultraviolet sources. Here, using a tunable free-electron laser, the authors obtain quantum yields for this channel showing that it is a possible route to prebiotic oxygen formation in interstellar environments.

The large, low-albedo asteroids in the main belt between 3.0 au and 3.4 au share spectral characteristics and history with Ceres. Accreted in different parts of the outer Solar System, they might have been implanted into the main belt by the dynamic upheaval created by the giant planets’ instability.

Vicinity of small bodies might be dangerous to the spacecrafts and to their instrumentation. Here the authors show the operational environment of asteroid Bennu, validate its photometric phase function and demonstrate the accelerating rotational rate due to YORP effect using the data acquired during the approach phase of OSIRIS-REx mission.

‘Oumuamua is the first interstellar interloper observed in our Solar System and studied in some detail. This Perspective reviews the data acquired during its visit and discusses its origin and properties, concluding that there is no basis to the theory of an artificial ‘Oumuamua.

Burial-dating methods using cosmogenic nuclides indicate that the oldest stone tools at Korolevo archaeological site in western Ukraine date to around 1.4 million years ago, providing evidence of early human dispersal into Europe from the east.

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.

A bright outburst of activity from the nucleus of comet 67P, observed by Rosetta in July 2015, is traced back to a cliff that partially collapsed at the same time as the outburst, establishing a link between the two events. The collapse has also exposed the fresh ice present under the surface.

Extraterrestrial organic matter found in meteorites may hold a unique record of its synthesis, and chemical and thermal alterations in the parent body, however, the origin of such aliphatics remains enigmatic. Here, the authors propose sequential gas-phase methyl-methylene addition growth of n-C₈H₁₈ to n-C₃₂H₆₆ alkanes based on a series of sputter gas aggregation source experiments and DFT calculations.

Chloromethane (CH3Cl) has been observed towards a low-mass protostar and comet 67P, making it the first organohalogen detected in space. The species was previously considered to be a biomarker, but the authors suggest viable alternative abiotic formation routes.

The history of Earth’s formation can be unravelled from the compositions of meteorites, terrestrial and lunar rocks, and observations from space-based telescopes. This Review discusses advances in theories and evidence concerning the dynamical mechanisms and timescales for Earth’s accretion in the Solar System.