Astrophysics has taken a key leap with the first direct image of a light exoplanet obtained by the James Webb Space Telescope (JWST). This finding highlights in the detection of TWA 7b, a gaseous world whose mass is close to that of Saturn and which becomes the least massive observed by direct photography.
So far, detecting light exoplanets It represented a first-class technical challengeTraditional methods relied on indirect clues, but this time, thanks to the advanced technology of the JWST and its coronagraph, TWA 7b has been observed without relying on these clues..
A young system, a window to the past
This exoplanet orbits the star TWA 7, a young star located about 34 light-years from Earth in the constellation Hydra. TWA 7 is a star system just 6,4 million years old, extremely young compared to our Sun, which is 4.600 billion years old.
The planet is located in the middle of a debris disk, formed by dust and rocks, in which three concentric rings stand out. The narrowest of these is flanked by two areas with little matter, and in its center, the infrared source has been located, which turned out to be TWA 7b. The image obtained has been essential to confirm the existence and mass of the exoplanet.
Thanks to the orientation of this disk, astronomers have been able to study the internal structures and verify, through simulations, how the gravitational action of TWA 7b could have sculpted the delicate ring and the hollow coinciding with its position.
An exoplanet, ten times lighter than others
The mass of TWA 7b is equivalent to 30% of that of Jupiter., the most massive planet in our system, and is close to the mass of Saturn. This is the case to date. In addition, It is ten times lighter than previously imaged exoplanets. by telescopes.
Obtaining direct images of such light planets represents a breakthrough important, since these techniques normally only allowed the detection of much larger gas giants. This technical progress .
The discovery was led by an international team, including Anne-Marie Lagrange of the French CNRS and the Paris-PSL Observatory, in collaboration with the University of Grenoble Alpes.
The coronagraph, key to the discovery
How is it possible to see something so small and faint? The coronagraph is a fundamental piece. It's a device that blocks the light from the main star, simulating what happens during a solar eclipse, so that very faint, nearby objects can become visible in their surroundings. Without this innovation, the light from the star TWA 7 would have prevented the discovery.
The MIRI instrument on the James Webb, equipped with the coronagraph developed in France, has demonstrated its ability to observe young, cold planets which still emit light in the mid-infrared, a window that, until now, had barely been used for the study of these worlds.
A step towards terrestrial exoplanets
The discovery of TWA 7b not only represents a technical record, but also a paradigm shift in research. The ability to photograph a Saturn-like planet brings astronomy closer to the real possibility of capturing images of small, solid worlds closer to our planet.
Although TWA 7b remains a gas giant, experts acknowledge that The James Webb technology has shortened distances regarding the detection of planets with conditions more similar to Earth, that is, terrestrial or potentially habitable.
This research shows that what until recently was unimaginable – seeing such light and distant planets in direct images – is becoming a tangible possibilityThe path to characterizing atmospheres and searching for habitable exoplanets has become much more accessible.
The discovery of TWA 7b marks the beginning of a new era in exoplanet astronomy. It's no longer just about discovering new worlds, but about being able to study them in detail and, in the future, even obtain information about their atmospheres and surfaces. Astronomy is preparing to look increasingly smaller, colder, and more elusive planets in the face, putting the idea of finding an Earth-like planet within the realm of the technically possible.