Media release

From: Springer Nature

Atomic oxygen has been directly detected both on the dayside and nightside of Venus, reports a Nature Communications paper. The method used enables detailed investigations of the region between the two atmospheric circulation patterns in Venus’ atmosphere, and may help support future space missions to Venus. Direct measurements of atomic oxygen may improve our understanding of why Venus’ atmosphere is so different to Earth’s, the authors suggest.

Venus is known to rotate very slowly, with one day on Venus lasting the equivalent of 243 Earth days. Atomic oxygen is produced on the dayside of Venus by the breakdown of carbon dioxide (CO2) and carbon monoxide (CO), and then transported to the nightside. Atomic oxygen is important for the photochemistry and energy balance of Venus’s atmosphere, but it has not yet been directly observed on the dayside of Venus. Nightside detections have previously been limited to observations of the night airglow of Venus, a faint emission of light by the planetary atmosphere.

Heinz-Wilhelm Hübers and colleagues analysed a total of 17 points on both Venus’ dayside and nightside using the upGREAT array spectrometer on board the Stratospheric Observatory for Infrared Astronomy (SOFIA) airplane. The authors detected atomic oxygen at all observed points, and found it to be concentrated at altitudes of around 100 km. The measurements were based on an atomic oxygen ground state fine structure at 4.74 Terahertz. They also found variations in the column densities, with a maximum density recorded on the dayside.