Traces of CO and another lethal gas, hydrocyanic acid, were found by a team of skywatchers led by Therese Encrenaz of the National Centre for Scientific Research (CNRS).

The CO was probably deposited by bombardment by micrometeorites, they said in a press release.

In contrast, very high levels of CO were found on Neptune, another distant gas giant, which suggests that this compound comes from the planet's interior.

The observations were made using infrared sensors at the European Southern Observatory's Very Large Telescope (VLT) in Chile.

SPACE.WIRE