Webb telescope provides exoplanet weather report

This was made possible with the help of measurement data from the ‘James Webb’ space telescope and climate models and simulations from the Graz Institute for Space Research, as the Austrian Academy of Sciences (ÖAW) announced on Tuesday.

WASP-43b orbits its star in a very close orbit. Using the infrared spectrometers of the “Webb” telescope (photo below), a complete orbit of WASP-43b, which always points to the same side of its central star as it orbits, was measured in a specific wavelength range.

Ludmilla Carone from the Institute for Space Research (IWF) of the ÖAW and her colleague Patricio Cubillos contributed to the interpretation of the measurement data. “Unfortunately, the conditions there are not friendly,” summarized Carone, who belongs to the exoplanets group at the IMF. The results have been published in “Nature Astronomy”.

Storms up to 18,000 kilometers per hour!
The temperatures in the atmosphere are therefore extreme: “On the day side we have temperatures of around 1250 degrees Celsius, on the night side it is a relatively mild 600 degrees, as shown by observation of the planet’s infrared radiation. The storms created by this enormous temperature gradient can reach speeds of up to 11,000 mph,” as Carone described.

The measurements also showed that clouds of mineral mixtures similar to those found in rocks on Earth are forming on the night side of the planet. No methane was measured on the night side. This suggests that the vertical mixing caused by updrafts is significantly stronger than initially thought: if it were calmer, the relatively cooler conditions would produce methane.

The IWF researchers contributed a three-dimensional climate and wind model to interpret the measurement data. Their predictions were compared with the measurement results and yielded “very good results”: “No model is perfect, but we are very satisfied with our results,” said Carone. The conditions on the dayside in particular were very well predicted. Patricio Cubillos’ atmosphere model in turn made it possible to analyze the methane and water content on both sides of the exoplanet.

“A new era of exoplanet research”
From Carone’s point of view, the first steps are being taken “towards a new era of exoplanet research”: “Once we have data from enough exoplanets, we can perform statistical analyzes that tell us how rare or common certain climatic conditions occur in the universe, for example those on Earth,” Carone emphasizes.

Furthermore, even more accurate measurements of exoplanets will further improve climate models and forecasts in the future – both for Earth and other planets, as the IMF said.