Articles in 2020

Pluto’s haze could have a major icy component created by the condensation of organic molecules such as C₄H₂. This is different from Titan whose haze, despite a similar atmospheric composition, is mostly macromolecular aggregates. Triton’s haze, instead, should be dominated by ices, particularly C₂H₄.

Flares from K and M dwarf stars drive change, and sustain an altered atmospheric chemistry, in orbiting rocky planets, according to a suite of three-dimensional climate models. The atmospheres of rocky planets around G dwarfs rapidly return to their pre-flare states, however.

A globular cluster-like system in the Galactic bulge hosts two stellar populations with remarkably different ages, identifying it as a site of recent star formation and providing observational proof for the hierarchical assembly of the Milky Way spheroid.

The observed oriented directions of galaxy angular momentum vectors correlate with predicted directions based on the initial density field reconstructed from the positions of Sloan Digital Sky Survey galaxies, opening a way to probe fundamental physics in the early Universe.

Two further radio bursts associated with magnetar SGR 1935+2154 have been detected with a Westerbork 25 m dish, bringing the total to four. These observations demonstrate that SGR 1935+2154, a putative Galactic analogue of a fast radio burst source, can emit bursts across seven orders of magnitude in energy.

Amino acid glycine is shown here to form in the laboratory at temperatures of <15 K without the need for energetic processing (such as ultraviolet irradiation or particle bombardment). The implication is that amino acids could potentially form at the very earliest stages of star formation and persist until planetary systems are established.

Based on laboratory experiments and predictions, the Europa Clipper mission is expected to detect the surface ices on the night side of Jupiter’s moon Europa glowing in the dark, with an intensity that can be used to determine their composition.

Observations of the jellyfish galaxy JO206 reveal an ordered, large-scale magnetic field and extremely high polarization, which can be explained by the accretion of magnetized plasma from the intergalactic medium that condenses onto the external layers of the tail.

A reconstruction of the distribution of cold traps on the Moon at spatial scales varying from 1 km to 1 cm shows that the smallest ones are also the most numerous, 10–20% of the total. The total surface area of the Moon that can efficiently trap water is revised substantially upward, to 40,000 km².

An asteroseismic and spectroscopic analysis of lithium-rich stars improves their classification based on the distributions of lithium, nitrogen and mass, and reveals that most of these evolved stars are red clump rather than red giant branch stars.

A five-membered carbon ring molecule, cyanocyclopentadiene, has been detected in a molecular cloud at a higher abundance than expected. This result from the GOTHAM survey indicates a rich aromatic chemistry in molecular clouds that is not fully understood theoretically.

MARSIS provides enhanced coverage of the south polar region where there have been indications of a subglacial lake. These new data confirm the presence of a lake and suggest the existence of a complex hydrologic system including various smaller liquid bodies, probably composed of salty brines.

Low-frequency quasiperiodic oscillations in X-ray data are thought to trace the accretion flow in X-ray binaries. Here, the detection of 200 keV oscillations probes the innermost regions of MAXI J1820+070, revealing the precession of a small-scale jet.

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.

Laboratory spectra of dust/ice aggregates are comparable to those observed in astrophysical environments, questioning the traditional onion-like layered ice model. According to observational spectra, such icy mixtures could harbour water ice in the diffuse interstellar medium, as well as in low-temperature circumstellar environments.

Multi-band high-resolution observations reveal very fast and bursty nanojets. These nanojets are a consequence of the slingshot effect from magnetically tensed, curved magnetic field lines reconnecting at small angles, resulting in coronal heating.

The detection of ~20 ppb of phosphine in Venus clouds by observations in the millimetre-wavelength range from JCMT and ALMA is puzzling, because according to our knowledge of Venus, no phosphine should be there. As the most plausible formation paths do not work, the source could be unknown chemical processes—maybe even life?

Multi-decade observations of Jupiter’s stratospheric temperatures show that their quasiperiodic oscillation locked into a new period after a major atmospheric perturbation in 1992, from 5.7 years to 3.9 years. This is different from Earth (and presumably from Saturn), where the period returned to its original value after substantial atmospheric disruptions.

Far-infrared polarimetric observations reveal a transition parallel to the gas flow in the orientation of magnetic field lines in the Serpens South molecular cloud, allowing gravitational collapse to occur even in the presence of strong magnetic fields.

Spectroscopic data obtained at high spatial resolution from Dawn detected the presence of fresh chloride salts at Cerealia Facula on Ceres. The spatial distribution of the hydration level of these salts suggests that they surfaced a maximum of a few centuries ago and that the upwelling of salty fluids may still be active.