The James Webb Space Telescope has directly imaged an exoplanet for the first time. This is exciting because it is very rare for exoplanets to be directly imaged, as usual their existence has to be inferred from other data. By creating an image of a planet outside our solar system, Webb shows how we can collect more information than ever before about distant worlds.
More than 5,000 exoplanets are known, but the vast majority of these have been detected using techniques such as the transit method, where the light from a host star drops slightly when a planet passes in front of it, or radial velocity, where a star is slightly swept away by the gravity of a host star. a planet. In these methods, the existence of a planet is inferred due to the effect that can be observed on a star, so the planet itself is not directly observed. In rare cases, however, an exoplanet can be directly observed, especially if it is a large planet that is relatively close.
Webb made such a direct observation of the exoplanet HIP 65426 b and was able to create an image of the planet using four different filters. Each of these filters corresponds to a different wavelength of light and captures different features of the planet and its environment. The planet is a large planet with between six and 12 times the mass of Jupiter, and it is a relatively young planet, only 15 to 20 million years old.
“This is a transformative moment not only for Webb but for astronomy in general,” Observer leader Sasha Hinkley said in a statement.
To observe the planet, the researchers had to shut out the light from the planet’s host star. Because the star is so much brighter than the planet, this light must be blocked in order to see the planet. This is done with an instrument called a coronagraph, a mask that blocks light from a bright source.
“It was really impressive how well the Webb coronagraphs worked to suppress the light from the host star,” Hinkley said.
“Getting this image felt like digging for space treasures,” said another of the researchers, Aarynn Carter. “At first I could only see the light from the star, but with careful image processing I was able to remove that light and expose the planet.”
This finding demonstrates some of Webb’s abilities when it comes to finding and researching exoplanets. “I think the most exciting thing is that we’re just getting started,” Carter said. “Many more images of exoplanets are coming that will shape our overall understanding of their physics, chemistry and formation. We may even discover previously unknown planets.”