Article by: Andacs Robert Eugen, on 25 April 2022, at 01:23 pm Los Angeles time

The Hubble Telescope allowed us to find answers to key questions about exoplanet atmospheres.

Some observations were made by a team of researchers at University College London (UCL) and were based on studies of 25 hot Jupiters detected by the NASA/ESA Hubble Space Telescope.

Among other findings, the team found that the presence of metal oxides and hydrides in the hottest atmospheres of the exoplanets was clearly correlated with the thermal reversal of the atmospheres, according to ESA.

"Hubble enabled the in-depth characterisation of 25 exoplanets, and the amount of information we learnt about their chemistry and formation - thanks to a decade of intense observing campaigns - is incredible," said the lead author, Quentin Changeat.

The team of astronomers set the goal from the beginning of the study to be able to answer 5 key questions about the atmosphere of the exoplanets.

Through this research, scientists want to know more about the composition of the atmosphere of exoplanets, the chemical elements that are there, and also the different characteristics that they may have.

The study's co-leader, Billy Edwards of UCL and the Commissariat à l'énergie atomique et aux énergies alternatives (CEA) said: "Our paper marks a turning point for the field: we are now moving from the characterisation of individual exoplanet atmospheres to the characterisation of atmospheric populations."

The help for the scientists was the Hubble and Spitzer space telescopes. Thus, the scientists used data from 600 hours of Hubble observations and 400 hours of Spitzer observations.

Among the most important data used were eclipse data from 17 of the 25 exoplanets in this study. Scientists say that eclipses of exoplanets can bring us important data about their atmosphere.

Among the most important data used were eclipse data from 17 of the 25 exoplanets in this study.

Scientists say that eclipses of exoplanets can bring us important data about their atmosphere.

One of the answers came from thermally inverted exoplanets.

What are their temperatures?

Well, scientists have found that exoplanets with a thermally inverted atmosphere are very hot, with temperatures above 2500 K, allowing metal species such as TiO (titanium oxide), VO (vanadium oxide), and FeH (iron hydride). to exist in their atmosphere.

But also a secondary question is: What is in their atmospheres?

The researchers concluded that they found TiO, VO, and FeH in all 25 atmospheres.

Why are the atmospheres of these exoplanets thermally inverted?

Scientists say that a logical explanation is due to the metal species TiO, VO, and FeH they contain.

All 3 species of metals are very efficient absorbers of stellar light.

Thus, very hot exoplanets may contain such species of metals, thus absorbing a large amount of light and heat, making the atmospheres have much higher temperatures.

So, thermally inverted.

And their explanation is correct, because they also discovered that very cold exoplanets (<2000 K) did not have thermal inversions, because they do not contain TiO, VO or FeH in the atmosphere.

"Many issues such as the origins of the water on Earth, the formation of the Moon, and the different evolutionary histories of Earth and Mars, are still unsolved despite our ability to obtain in-situ measurements. Large exoplanet population studies, such as the one we present here, aim at understanding those general processes," said Changeat

The study allows us to see general results because it was done on 25 exoplanets. If it was only done on one or two, it wasn't very relevant.

Source: IOP