Opinion – Sidereal Messenger: Webb Telescope observes CO2 in exoplanet atmosphere for the 1st time

by

For the first time, astronomers have obtained incontrovertible evidence of the presence of carbon dioxide (CO2) in the atmosphere of a planet outside the Solar System. Success is just a small sample of the revolution that the James Webb Space Telescope promises for years to come.

The exoplanet in question, Wasp-39 b, is a gas giant, about a quarter the mass of Jupiter and 30% larger in diameter. The reason for the larger size with the smaller mass has to do with its orbit: it resides very close to its parent star, completing each turn in just over four Earth days. As a result, it is very hot (about 900 ° C), which makes it appear much more swollen than our Jupiter.

During its first battery of scientific observations, Webb was scaled to point its primary mirror toward the star Wasp-39 when the gas giant was passing in front of it, a phenomenon known as a planetary transit (think of it as a mini-eclipse). With the alignment, the telescope can capture the star’s light that grazes the edges of the planet’s atmosphere before reaching here. It carries with it the signature of the molecules it encountered along the way. Astronomers call the analysis of light for these chemical trails transmission spectroscopy.

The Hubble and Spitzer telescopes had observed Wasp-93 b before, with which they had detected the presence of water vapor, sodium and potassium in its atmosphere. Carbon dioxide, however, is an unprecedented finding, the result of the detailed spectrum produced by NIRSpec (Near Infrared Spectrograph), one of the four Webb instruments.

There is nothing surprising about the detection, which is described in a study already accepted for publication in the British scientific journal Nature. But what delights scientists is the level of precision and quality observed in the spectrum collected by Webb. The expectation is now to see what similar observations will reveal not with gas giants, but with rocky-type planets.

The result cheers Natalie Batalha, an astronomer at the University of California at Santa Cruz and leader of the team responsible for the discovery. “Detecting such a clear signal of carbon dioxide in Wasp-93 b is a good signal for detecting atmospheres on smaller, terrestrial-sized planets,” she said.

Another interesting aspect is that the work is part of an early Webb results release program that involved observing several other exoplanets of interest, with all instruments, to quickly provide the astronomical community with data and tools that will be the basis of the efforts. of more focused observation that will come later. That is, there’s a lot more news about worlds outside the Solar System coming, and it’s quite possible that the discovery of the first confirmed habitable exoplanet (capable of harboring liquid water on the surface) is just around the corner.

This column is published on Mondays, in Folha Corrida.

Follow the Sidereal Messenger on Facebook, twitterInstagram and YouTube

You May Also Like

Recommended for you