Volume 7 Issue 1, January 2023

Data from the gravitational wave event GW190521 can be explained by a semi-analytical model of two stellar-mass, nonspinning black holes on highly eccentric, hyperbolic orbits that undergo two close encounters before merging into an intermediate-mass black hole.

Solar wind observations from the Magnetospheric Multiscale mission reveal bursty, turbulent properties within a reconnection diffusion region, in contrast with the usual quasi-steady state of solar wind reconnection. Between October 2017 and May 2019 75 other similar events were identified, indicating the relevance of turbulent reconnection in the solar wind.

Oxygen isotopic measurements from the Ryugu returned sample suggest that primitive hydrated carbonaceous chondrites are an important source of early water and other volatiles to Earth, despite being underrepresented in our meteorite collection due to their preferential destruction during atmospheric entry.

Observational evidence from planetary systems around white dwarfs shows that planetesimal formation occurs during the first few hundred thousand years after cloud collapse. Iron accreted by these white dwarfs must have been formed by short-lived radioactive nuclides driving iron core formation in planetesimals that form together with the parent star.

An ultraviolet- and carbon-rich environment is needed to explain the bright emission coming from complex organic molecules observed near the midplane of protoplanetary disks. This implies that the gaseous reservoir from which actively forming planets accrete is carbon and organic rich.

Exoplanets with radii between 1.4 and 2.5 R_⊕ may have atmospheres strongly enhanced in helium after a few billion years, due to the preferential loss of hydrogen over helium via photoevaporation. If observed, this phenomenon could demonstrate the importance of photoevaporation in shaping the radius valley.

Early emission from gamma-ray burst GRB 211211A comes entirely from charged particles accelerating in strong magnetic fields. The fast-evolving spectrum may be the key to understanding unusually long-lived GRBs from neutron star mergers.

Simultaneous polarimetry measurements in the optical and radio bands for the afterglow emission of GRB 191221B provide insights into particle acceleration and total energy budget of gamma-ray bursts.

By modelling the radio, optical, UV and X-ray data of the unusually bright cosmological explosion AT 2022cmc, Pasham et al. argue for the presence of a highly collimated jet moving at ≳99.99% the speed of light.

Individual productivity among astronomers was boosted during the COVID-19 pandemic, but the improvement was not shared equally between men and women: a smaller fraction of papers were written by female astronomers and fewer women were among incoming new researchers in many countries.

Quantum sensors, such as atomic clocks, placed deep into the inner Solar system, may be sufficiently sensitive to directly detect ultralight dark matter bound by the mass of the Sun.