An artist’s impression of a giant exoplanet orbiting close to its star. Image: Amanda Smith
A team of researchers, led by the University of Cambridge, used atmospheric data from 19 exoplanets to obtain detailed measurements of their chemical and thermal properties. The exoplanets in the study span a large range in size – from ‘mini-Neptunes’ of nearly 10 Earth masses to ‘super-Jupiters’ of over 600 Earth masses – and temperature, from nearly 20°C to over 2000°C. Like the giant planets in our solar system, their atmospheres are rich in hydrogen, but they orbit different types of stars.
The researchers found that while water vapour is common in the atmospheres of many exoplanets, the amounts were surprisingly lower than expected, while the amounts of other elements found in some planets were consistent with expectations. The results, which are part of a five-year research programme on the chemical compositions of planetary atmospheres outside our solar system, are reported in The Astrophysical Journal Letters.
“We are seeing the first signs of chemical patterns in extra-terrestrial worlds, and we’re seeing just how diverse they can be in terms of their chemical compositions,” said project leader Dr Nikku Madhusudhan from the Institute of Astronomy at ...