The JWST has observed its first exoplanet, and astronomers are jubilant

The king of telescopes adds a new observation described as “historic” by specialists to his hunting list.

The James Webb Space Telescope has already graced us with a slew of grandiose shots since its first contributions were unveiled on July 12 (see our article). Today, he returns with new material that is less aesthetically striking, but at least as interesting from a scientific point of view: here is the very first image of an exoplanet captured by NASA’s new spearhead.

We rediscover HIP 65426 b, a gas giant which has not stolen its qualifier; it is indeed five to ten times more massive than Jupiter, the immense matriarch of our solar system which is itself approximately 320 times heavier than the Blue Planet. It is, however, much younger than our planet at around 4.5 billion years old, with around 15 million years on the clock.

This is already a date that will go down in history according to the astronomers behind this work, even if other telescopes have already documented HIP 65 426 b before. ” This is truly a historic moment for astronomy exults Sasha Hinkley, professor of astronomy affiliated with the University of Exeter interviewed by the Guardian.

Exoplanets hide in bright light

And the research team has every reason to be delighted. Indeed, directly observing exoplanets is a very delicate exercise; these are objects that are traditionally not very bright, and therefore not easy to visualize. But the main difficulty comes mainly from the presence of neighboring stars. Their brilliance, which is much greater than that of neighboring objects, tends to hide the latter; capturing a direct image of an exoplanet is a bit like trying to photographing the light of a candle next to a lighthouse miles away.

This observation also applies to state-of-the-art telescopes; they too have a lot of trouble producing portraits of usable exoplanets. Even the most powerful of them have to employ a combination of filters and post-processing; otherwise, the star will inevitably “photobomb” the image. A limit that tends to deprive astronomers of certain very fine and potentially decisive details.

The first exoplanet observed in infrared

And it’s starting to become a habit, but again, this is a scenario where the exceptional performance of the JWST will completely change the situation. This observation is a bit special since it is the first time that an exoplanet could be observed in the infraredthe wavelength at which this 10 billion dollar gem operates.

This new approach has already allowed astronomers to observe HIP 65 426 b at wavelengths that were completely invisible to them until then, despite the fact that it is about 10,000 times fainter than its star! They were therefore able to collect much finer details than usualin particular on its mass and its temperature.

For example, these observations have already shown that its atmosphere is a real furnace; its temperature is around 1300°C. According to the researchers, this suggests that it probably contains large amounts of silicate dust. An element that would then give it a nice crimson hue when observed in real colors.

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©NASA

The JWST, the future best friend of exoplanet hunters

Ultimately, they believe that the incredible precision of James Webb will allow them to go much further; for example, they hope to be able to directly study meteorological variations in the atmosphere of the targeted planets. Remember that the machine has recently been able to identify specific chemical elements in the atmosphere of exoplanets (see our article).

We can therefore expect the study of exoplanets to progress at high speed in the years to come. So there is plenty to be very excited about; this is another very interesting angle of attack for studying the structure and dynamics of the universe on a large scale, the conditions for the appearance of life forms, and so on.

Incidentally, these works show once again that the JWST is not just a galaxy hunter; he will make outstanding contributions in many areas of space science. ” The James Webb will open the door to a whole new class of planets that have until now been completely beyond our reach “Summarizes Hinkley in a pensive tone.

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