Queen’s researchers have collaborated with a team of International astronomers to use the NASA/ESA Hubble Space Telescope and the NASA Spitzer Space Telescope to study the atmospheres of ten hot, Jupiter-sized exoplanets in detail - the largest number of such planets ever studied.

The team was able to discover why some of these worlds seem to have less water than expected — a long-standing mystery, with their results published today (Monday 14 December 2015) in the Nature journal.

Until now, astronomers have discovered nearly 2000 planets orbiting other stars. Some of these planets are known as hot Jupiters — hot, gaseous planets with characteristics similar to those of Jupiter. They orbit very close to their stars, making their surface hot, and the planets tricky to study in detail without being overwhelmed by bright starlight.

Due to this difficulty, Hubble has only explored a handful of hot Jupiters in the past, across a limited wavelength range. These initial studies have found several planets to hold less water than expected.

Now, an international team of astronomers has tackled the problem by making the largest ever study of hot Jupiters, exploring and comparing ten such planets in a bid to understand their atmospheres. Only three of these planetary atmospheres had previously been studied in detail; this new sample forms the largest ever spectroscopic catalogue of exoplanet atmospheres.

Dr Neale Gibson from the Astrophysics Research Centre at Queen’s School of Mathematics and Physics is one of the authors of the study. He said:

“Planets are probably the most diverse astronomical bodies in the universe, and outnumber the stars, but until now we have only been able to look at the planets in our own Solar System and a handful of others. For the first time this study reveals the diversity of 'hot Jupiter’ atmospheres, and has enabled us to finally solve a long-standing problem in exoplanet science.”