Research articles

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 optical follow-up and analysis of two neutron star–black hole merger candidates with the Zwicky Transient Facility did not yield viable counterparts. However, state-of-the-art kilonova models constrain the ejecta properties of these mergers.

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?

LTT 9779 b is Neptune-sized planet rotating around its star with a period of 0.79 days and an equilibrium temperature of 2,000 K. It is not clear how it retained its atmospheric envelope, which contains ~10% of H/He, as it should have been photoevaporated by now.

Three different layers can be distinguished in the first 500 metres of depth beneath the South Pole–Aitken basin on the Moon: a first layer made up by regolith and ejecta material from different craters, followed by a middle unit of mare basalts and finally a >200-m-thick layer of ejecta from the Leibnitz crater.

The detection of Lyman continuum emission with a high escape fraction from a low-mass clumpy galaxy at z = 1.42, in a redshift range where previously no similar sources were detected, opens up a new window to constrain the shape of the ionization spectrum.

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.

Ten years of gamma-ray data reveal emission in the vicinity of the microquasar SS 433 that is co-spatial with an interstellar gas enhancement and varies periodically at the precessional period of SS 433, challenging existing theoretical models.

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.

High-resolution gravity data from Dawn’s second extended mission could probe the global and local structure of Ceres’s crust. The results show significant spatial and vertical variations of crustal density and porosity, associated with ice features and ice-related processes driven from the interior, and impacts.

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.

High-spatial-resolution images of the bright points at Occator crater on Ceres, taken during the second extended Dawn mission, allowed reconstruction of the chronology of their formation. The area experienced extensive cryovolcanism less than nine million years ago that lasted several million years, indicating recent geological activity.

High-resolution data of Ceres’s bright spots (faculae), obtained by Dawn’s second extended mission, suggest the existence of a deep brine-rich reservoir that emerged to the surface through long-lived cryovolcanic activity as a consequence of the impact that created Occator crater.

Global images of helium and hydrogen emission are used to directly derive the helium abundance out to 2.2R_⊙. The helium abundance is shaped by the large-scale coronal magnetic field. Helium is almost completely depleted near the equator in the quiet Sun.

A large streamer of infalling material joins the dense core with the accretion disk around a young protostar, where the streamer is linked to disk structures. This finding demonstrates the importance of a big-picture viewpoint when studying small-scale accretion features.

Observations of the X8.2 solar flare, which happened on 2017 September 10, could spatially resolve the distribution of the energetic electrons along the reconnection current sheet. More than 99% of them are concentrated at the bottom of the current sheet, not at the reconnection X point.

Stellar intensity interferometry (SII) is undergoing a revival. Here, data from the four 12 m optical reflectors of the VERITAS array are correlated post facto to determine the angular diameter of two stars to a high precision, laying the groundwork for SII at future large Cherenkov arrays.

Conditions in an accretion burst around a high-mass young stellar object (HMYSO) were sufficient to pump two species previously not known to maser. HDO and HNCO were found to trace spiral-arm features in the accretion flow onto the HMYSO.