A maximum of 1250 degrees with an 8000km/h breeze

Artist's impression of an exoplanet. | Newsreel
An artist's impression of exoplanet WASP-43 b. | Photo: Raif Crawford (NASA)

Winds exceeding 8000km/h, daytime temperatures of 1250 degrees Celsius, dropping to 600 degrees overnight. That’s the environment of a planet 280 light years away.

An international team of researchers has mapped the weather – including temperature, cloud cover and winds – on the exoplanet in a demonstration of the science now possible with the James Webb Space Telescope’s ability to measure temperature variations and detect atmospheric gases trillions of kilometres away.

Dr Tom Evans-Soma, from the University of Newcastle in northern New South Wales co-authored a study published in Nature Astronomy which analysed some of the first data returned by the telescope trained in the region of exoplanet WASP-43 b.

From the observations, the team gleaned that dayside on the exoplanet boasts clear skies with an average temperature of nearly 1250 degrees Celsius – almost hot enough to forge iron.

“Meanwhile, the nightside was significantly cooler at 600 degrees Celsius with thick, high cloud coverage,” Dr Evans-Soma wrote.

The data revealed a surprising lack of methane anywhere in the atmosphere, a clue which suggests to scientists that the exoplanet has high wind speeds upwards of 8000 km/h.

“At wind speed this high there isn’t enough time for the expected chemical reactions to produce detectable amounts of methane.”

Exoplanets are planets that are located beyond our solar system.

WASP-43 b is a “hot Jupiter” type of exoplanet i.e. similar in size to Jupiter, made primarily of hydrogen and helium, and much hotter than any of the giant planets in our own solar system.

Read the study