Astronomers find evidence of weather change on a giant gas planet larger than Jupiter

A team of astronomers have found evidence to show signs of changing weather in the atmosphere of a giant gas exoplanet almost twice the mass of Jupiter.

This is the first direct evidence of variations in the weather on a gas giant, over a thousand light years away, in another solar system.

This breakthrough will enable astrophysicists to explore how weather systems on other planets outside of the solar system can change over time, especially considering upcoming space missions, such as the European CHEOPS and PLATO satellites.

Dr Ernst de Mooij, a newly appointed Lecturer in the School of Physical Sciences at Dublin City University made the significant discovery in collaboration with research teams from the University of Warwick, led by Dr David Armstrong; Queen’s University Belfast and University College London.

The discovery was made on exoplanet HAT-P-7b, which is 40% larger than Jupiter and orbits a star twice as large as the sun.

The findings “Variability in the atmosphere of the hot giant planet HAT -P-7b” are published in the prestigious Nature Astronomy journal.

Researchers used data from NASA’s Kepler satellite to monitor variations in the light intensity from the planet HAT-P-7b as it orbits its star. This is called the phase-curve of the planet and the variations are caused by the day-side of the planet rotating in and out of view.

Commenting on the findings Dr Ernst de Mooij, Dublin City University School of Physical Sciences said:

“Up to this point we have been combining all the data from the entire Kepler mission together to get the most precise measurements possible. In this new research, we combined only a few orbits of the planet, allowing us to monitor changes in the planet’s atmosphere on timescales of days and weeks.”

The team found changes in the brightness and heat of the planet, depending on the time of day on the planet. At some points, the brightest part of the planet’s atmosphere was located on the morning side while during other periods the afternoon side was brighter.

The change is thought to be caused by an equatorial jet with variable wind-speeds. It is also thought that the night-side of the planet, although extremely hot by Earth’s standards, was cool enough for exotic materials, to condense and form clouds, which were then transported to the planet’s day-side where they evaporate again.