Research Briefing

Phase-curve observations of the ‘hot Jupiter’ exoplanet WASP-43b, made at mid-infrared wavelengths using JWST, provide evidence that fast winds limit the formation of methane on the cooler, cloudy nightside of the planet.

Based on physical modelling and using deep-learning tools, a 3D reconstruction of a flare orbiting the black hole Sagittarius A*, at the centre of the Milky Way, provides observational clues to the formation of high-energy flares and the dynamics of black-hole accretion disks.

What mechanisms power the heating of the solar atmosphere is a long-standing, complex question. Satellite and sounding-rocket observations, coupled with computer simulations, now support the idea that dissipation of electrical currents causes strong heating in the brightest parts of the solar chromosphere and corona.

The successful impact of NASA’s DART on Dimorphos, the moon of asteroid Didymos, has been analysed using advanced numerical simulations. The results reveal the asteroid’s low surface cohesion and rubble-pile structure, similar to what has been observed on asteroids Ryugu and Bennu.

Cosmic dust contains all the elements needed for life but has previously been considered too rare to have acted as a ‘fertilizer’ for prebiotic chemistry. Now, using a combination of astrophysical and geological models, it is revealed that cosmic dust could have gently accumulated on the surface of early Earth in sufficient quantities to promote the chemical reactions that led to first life.

The observed ‘radius valley’ — a dip in the distribution of exoplanet radii, which separates rocky super-Earths from larger sub-Neptunes — is at odds with current theories of planetary formation. New simulations that couple planet formation and evolution, and account for the orbital migration of planets that are largely composed of steam, are able to reproduce the valley feature.

The Lyman-α emission line of hydrogen should be absorbed and thus not seen from galaxies in the early Universe — and yet it is observed. Now detailed images from JWST coupled with magnetohydrodynamical simulations show that interactions between galaxies are facilitating the escape of this radiation.

High-mass stars in the Milky Way often exist in systems of two or more stars, but how this multiplicity arises is not clear and so far there have been no unequivocal observations of protostellar systems that could solve the issue. Now, systems of five, four and three stars, and several binaries, have been resolved in a star-forming region, and point to core fragmentation as the likely origin of multiplicity.

Periodic sub-structure in radio emission from magnetars provides an observational link not only between magnetars and fast radio bursts, but across all classes of radio-emitting rotating neutron stars. The correlation between sub-structure periodicity and neutron-star rotational period can be used to determine an underlying period for fast radio bursts.

The optical properties of the organic hazes that form in water-rich exoplanet atmospheres differ from those that form in nitrogen-rich atmospheres. This difference in optical properties can have an observable effect on spectral observations of exoplanets and could impact the interpretation of current and upcoming JWST observations.

Theories predict that core asphericity must be involved in core-collapse supernova explosions; however, the shape of these explosions has not been directly observed. The distribution of the explosive burning ash has now been revealed using nebular spectroscopy, indicating that a collimated structure is common in many stellar explosions.

Fast radio bursts, arriving at Earth from distant galaxies, usually have durations of a few milliseconds or more. Now, data on a source of repeating fast radio bursts have been revisited, with much higher time resolution than before, and burst signals are seen that last only a few microseconds — showing that the properties of fast radio bursts are more diverse than previously thought.

JWST observations of Jupiter reveal a narrow and intense atmospheric jet at the equator of the planet, close to its tropopause. The jet is manifest in the fast motions of equatorial hazes and is most likely a deep counterpart of the equatorial oscillations observed in Jupiter’s stratosphere.

Through the past 12 billion years of cosmic time, galaxies have been in a near-equilibrium state, with their star-formation rates, stellar masses and chemical abundances tightly connected. But, from JWST observations, it now seems that at earlier times galaxies deviated from this relation, owing to the inflow of pristine gas in the early Universe.

Carbon atoms are one of the most abundant chemical species in the earliest stages of star formation. They had been thought to be immobile on the surface of interstellar ice, but laboratory experiments now show that a significant fraction of carbon atoms can move on the surface and react — changing our view of interstellar organic chemistry.

The Chang’e-6 mission plans to return geological samples from the farside of the Moon by 2025. The spacecraft will land in the four-billion-year-old Apollo crater within the South Pole–Aitken basin: three candidate sites within the crater have been identified and their scientific potential for sample collection has been explored.

The 21-cm absorption lines from neutral hydrogen at cosmic dawn are proposed as a probe to simultaneously study dark matter particle mass and cosmic heating history. By applying a statistical approach to simulated data this probe is shown to distinguish the effects of dark matter from those of cosmic heating.

A dedicated method for analysing moderately saturated measurements from Swift’s Ultraviolet and Optical Telescope is used to perform a time-resolved analysis for the initial white filter exposure of GRB 220101A. This analysis reveals a rapidly evolving ultraviolet and optical flare, distinguished by extremely high luminosity and unexpected temporal behaviour.

Cosmological surveys aim to constrain the ‘gravitational slip’, a key signature of modified gravity — but an as-yet unknown force acting on dark matter could mimic the gravitational slip and invalidate the test. By additionally factoring in a measurement of gravitational redshift, future surveys could have the power to distinguish between these possibilities.

Observations using JWST show water, probably from a subsurface ocean on Saturn’s icy moon, spewing into a large plume that extends far beyond the moon’s surface. This continuous outgassing results in a torus of water along Enceladus’s orbit and is so intense that the plume is the prime source of water across the Saturnian system.