Volume 4 Issue 9, September 2020

Analysing greenhouse gas emissions of an astronomical institute is a first step to reducing its environmental impact. Here, we break down the emissions of the Max Planck Institute for Astronomy in Heidelberg and propose measures for reductions.

Measuring the carbon emissions of the CFHT in 2019 reveals that the per employee emissions are 16.5 tCO₂e, six times above the recommendation of the Paris Agreement, with ~63% due to the electricity consumption of the summit facility and ~25% to out-of-state air travel. Concerted efforts are underway to reduce this figure.

Computer use in astronomy continues to increase, and so also its impact on the environment. To minimize the effects, astronomers should avoid interpreted scripting languages such as Python, and favour the optimal use of energy-efficient workstations.

The annual meeting of the European Astronomical Society took place in Lyon, France, in 2019, but in 2020 it was held online only due the COVID-19 pandemic. The carbon footprint of the virtual meeting was roughly 3,000 times smaller than the face-to-face one, providing encouragement for more ecologically minded conferencing.

Climate change is affecting and will increasingly affect astronomical observations, particularly in terms of dome seeing, surface layer turbulence, atmospheric water vapour content and the wind-driven halo effect in exoplanet direct imaging.

The interstellar object ‘Oumuamua passed through the Solar System in 2017 and exhibited a puzzling combination of physical features. New work tells the story of this visitor.

The upper atmospheres of all the giant planets are hotter than models predict. Analysis of Cassini Grand Finale observations of Saturn provide evidence that heat generated by the aurora is responsible.

A Galactic wind blowing from the Milky Way nucleus has swept up a few hundred clouds of atomic gas. New observations reveal dense molecular cores in two of these clouds, indicating a high loss rate of interstellar gas from the Galactic centre.

The annual Fast Radio Burst conference was held as an entirely virtual event on 6–9 July inclusive, with talks spread over three time zones and an online communication channel for discussions.

Australian astronomers generate more greenhouse emissions than the average Australian citizen, thereby exacerbating the climate crisis. By quantifying contributions from different activities such as supercomputing and air travel, as presented here, astronomers can focus on reducing emissions by changing their practices in the most critical areas.

Tidal fragmentation of a planetary body that orbited too close to its star can explain all the peculiar characteristics of the interstellar visitor ‘Oumuamua, a formation model shows. Kilometre-sized comets, super-Earths and sub-Neptune exoplanets around subsolar stars or white dwarfs are the most probable parent bodies.

Interstellar comet Borisov has thus far looked very much like a Solar System comet in terms of its volatile content, but with new data from ALMA that show robust detections of CO and HCN, it is clear that Borisov is rich in CO, helping to pinpoint its origin.

Hubble Space Telescope data show that interstellar comet 2I/Borisov has an unusually high CO/H₂O ratio—higher than any other comet that has been seen in the inner regions of our Solar System. This allows us to constrain the nature and location of the circumstellar region from which 2I/Borisov originated.

The complete latitudinal coverage of Saturn’s thermospheric temperatures from Cassini Grand Finale data shows a more uniform spatial behaviour than model predictions, indicating an efficient redistribution of auroral energy from the poles towards the equator that could contribute to solving the giant planet’s energy crisis puzzle.

It is difficult to reproduce the formation and composition of the moons of Uranus with a standard giant-impact model. Observations and modelling can be reconciled if the evolution of the water content in the disk, which is assumed to be vaporized and thus mostly accretes onto the planet before recondensation, is considered.

Cataclysmic variables—a binary pairing of a white dwarf and a hydrogen-rich donor star—experience mass transfer and other complex interactions. This numerical simulation by Hillman et al. models in particular the feedback between the stellar pair, and succeeds in reproducing many of the observed characteristics of cataclysmic variables.

A recent supernova event, SN2016aps, must have involved an extremely energetic explosion and a very massive star, potentially indicating a pair-instability supernova or pulsational pair-instability supernova mechanism.

High-resolution radiation-hydrodynamic simulations of galaxy clusters show that extended cold gas filaments can form in the centre of clusters through the combination of radiative cooling and ram pressure from feedback driven by the central active galactic nucleus.

Optical communications will provide the next generation of interplanetary missions with high-bit-rate data transmission, requiring modifications on the ground and in space, explains Leslie Deutsch.