James Webb Telescope celebrates a year of science – 07/12/2023 – Science

From objects in our Solar System to nearby exoplanets, passing through the great nurseries of stars, the galactic neighborhood and the outer reaches of the Universe, the James Webb Space Telescope is now completing a year of scientific operations with overwhelming demonstrations of its potential to take astronomy, in its various dimensions, to a new level, revealing the most subtle secrets of the cosmos.

To celebrate the date, remembering the fact that the first scientific image of Webb, a deep field of galaxies, was presented on July 11 last year at an event with President Joe Biden, at the White House, NASA released this Wednesday (12) A new image produced by the Space Telescope, and this time the target is closer to home—in more ways than one.

This is the Rho Ophiuchi cloud complex, a nebula located 390 light years from Earth, in the constellation of Ophiuchus. It’s the closest known stellar nursery, and the space telescope image is breathtaking. First, by revealing about 50 stars, most the size of the Sun or smaller, in the process of forming, in detail never captured before.

Thanks to its 20-foot (6.5-meter) primary mirror and a keen infrared eye, Webb reveals a mix of formed stars and dust-shrouded cocoons, some of them exposing the signs of protoplanetary disks—indicating that, along with stars, they are collapsing. forming planets. At the center of the image is the largest of the newborn stars, significantly more massive than the Sun and capable of, with its ultraviolet radiation, opening an empty pocket in the middle of the nebula, sweeping the gases away.

In addition to its beauty (you can’t go wrong when the target is nebulae), what you see is an auspicious scenario not only for studying the formation of new stars, but for understanding how the Sun and its family of planets came to be. to emerge. In some cloud like this, 4.6 billion years ago, the Sun was forming. While the image itself reveals the state of this nebula just 390 years ago (since that’s the time it took light to travel from there to here), its reach towards understanding the past is much broader.

The study of nebulae that serve as stellar nurseries is no longer the same after Webb. But this is just one of the areas of research that the space telescope developed at a cost of US$ 10 billion by Americans, Canadians and Europeans (united in the NASA, CSA and ESA agencies, respectively) has already begun to transform, for the better, into its first year of scientific observation.

“The scientific breadth that Webb is able to explore is really clear now, having a year’s worth of data coming from targets scattered across the sky,” says Eric Smith, deputy director of research in NASA’s astrophysics division and a scientist directly involved. with the space telescope. “Webb’s first year of science has not only taught us new things about our Universe, but has revealed that the telescope’s capabilities are even greater than our expectations, indicating that future discoveries will be even more amazing.”

Solar system

It is not the main highlight, nor the main reason for building the Webb, but the telescope shone in this first year in the field of planetary science, which involves the study of objects in our own Solar System. Webb cannot be pointed at Mercury and Venus, the innermost planets, lest it risk exposing the mirror and its instruments to the Sun, but from Mars onwards it’s all game.

In this first year, landmark observations of the gas giant planets were carried out. In the infrared, it sees details that other telescopes just can’t pick up. A great example were the images of Uranus and Neptune, the most distant planets.

“On Neptune, we haven’t seen some of the rings since Voyager-2 flew by in 1989,” says Macarena Garcia Marin, an astrophysicist at ESA and a scientist involved with the telescope. “With Webb, we can see all these features, we have more data, and astronomers are looking for more rings, more satellites, and can study in more detail the atmosphere and dynamics of these planets.”

The equipment also proved to be more versatile than expected. Accidentally, he discovered the smallest asteroid ever seen in the belt between Mars and Jupiter, just 200 meters long. And he made an observation that left the responsible scientists stunned: the monitoring, in real time, of what happened to the asteroid Dimorfo after the Dart spacecraft collided with it.

“It was a challenge,” says Jane Rigby, an astrophysicist at NASA’s Goddard Center for Space Flight and a senior scientist at the Webb. “It wasn’t designed to track an object that was moving that fast — it was three times the telescope’s predicted maximum travel speed — and yet we were able to track the plume of debris exiting the asteroid when it was impacted by Dart.”

In practice, the attempt redefined—for the better—the ability to track fast-moving objects across the sky.

exoplanets

Jumping out of the Solar System, Webb observed several stars in the most varied stages of their lives, including the Wolf-Rayet, which are unstable stars at the end of their lives, and planetary nebulae, the remains of stars that have already died. The biggest highlight, however, was the study of exoplanets, an effervescent field of astronomy that already has more than 5,000 stars discovered in the last three decades.

“We’re spending a lot of time studying exoplanets,” says Rigby. “Webb wasn’t built to observe them. That goal was added kind of at the end, in the spirit of ‘let’s see what we get.’ we — wow, there are the signatures of the molecules.”

One of the great uses of Webb is to monitor when an exoplanet passes in front of its star, causing a minieclipse. Some of the light from it skims through its atmosphere before reaching us, bearing the signature of the gases it encounters along the way. And the telescope boasts unrivaled quality compared to its more famous siblings like the Hubble Space Telescope. “We used to get maybe one molecule. Now we get a complete set, water, carbon dioxide, carbon monoxide,” says Rigby.

One of the main targets in this field studied by Webb in this first year of observations was the Trappist-1 system. Located 41 light-years from Earth, it has 7 terrestrial-sized planets, 3 of which are in the habitable zone – neither too hot nor too cold – around the star, a modest red dwarf much smaller than the Sun. By that time, results had already been published for the two innermost planets, Trappist-1 b and c, which identified the absence of appreciable atmospheres and daytime temperatures of around 230°C and 110°C respectively. “For the time being we have results for the two most internal ones, and we are working on the characterization of the others”, says Marin.