OSSO in the atmosphere of Venus

Associate Professor Jo Lane and his collaborators at Copenhagen University have published an interesting new paper in atmospheric chemistry: Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere.

The atmosphere of Venus is much hotter and denser that that of Earth. It primarily consists of carbon dioxide (CO₂, 96.5%)  and nitrogen (N₂, 3.5%), with traces of other gases, most notably sulfur dioxide (SO₂). With nearly 30 successful space missions to Venus, scientists have a pretty good understanding of most of its atmospheric chemistry. However, there is an unknown molecule present in the atmosphere of Venus that strongly absorbs ultraviolet (UV) light from 320-400 nm. And while many possible molecules have been considered, none so far have been demonstrated a good fit to the experimental observations.

It has been suggested that disulfur dioxide (OSSO), could be responsible for the absorption of UV light in the atmosphere of Venus. However, it is extremely challenging to make OSSO and record its absorption spectrum under the conditions present on Earth. Jo and his collaborators used sophisticated computational chemistry methods to simulate the absorption spectrum of OSSO, as well as a series of related sulfur-oxygen molecules to benchmark the accuracy of their approach. The simulated spectrum for OSSO was found to match closely with the unknown absorbance from 320-400 nm, which suggests that this is due to OSSO.

Read the full research publication Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere.