Astronomers believe that planets revolve around every star, and our sun is just one of them. About five thousand of these “exoplanets” are now known, which is a tiny fraction of the total number. But direct observations of exoplanets are rare: In the bright light of a parent star, the exoplanet is faint like a fly on a beacon. Add to this the sheer distance – at least four hundred light-years in this case – and it is understandable why there are only twenty profiles of five thousand known exoplanets.
However, the planet in question, called “HIP 65426 b”, was actually photographed in 2017. This “second” observation excites a lot in the astronomical world. If not by the model, then by the photographer: the James Webb Space Telescope. Using the latest instruments and the largest lens ever for a space telescope, James Webb can make entirely new observations, even on known planets.
Previously invisible light
This is partly because the telescope is unaffected by particles scattered in Earth’s atmosphere, which telescopes on Earth still have to look through. In addition, James Webb is located at a strategic distance from Earth, so that the space telescope is less affected by disturbing radiation from Earth.
This allows James Webb to perceive light that was previously invisible, even to the Hubble telescope that preceded it. A lot of information about exoplanets, for example about clouds in the atmosphere, is neatly hidden in those inaccessible “colors” of light. That’s why planetary scientists have been eagerly awaiting Webb’s first shots of exoplanets.
“It’s like you want to look into a room, but you can just look through the keyhole in the door,” says Ignas Snellen, a professor of exoplanets at Leiden University who was not involved in the research. “With James Webb, we can finally open the door and really look inside.”
Date
For example, astronomers can now gather information about the chemical composition of exoplanets. This was also evident when James Webb recently detected carbon dioxide in the atmosphere of an exoplanet, for the first time. Researchers are interested in these types of chemical discoveries because they can provide valuable information about the evolution of exoplanets.
The depicted planet is relatively young – it is only 14 million years old. By comparison, the Earth formed about 4.5 billion years ago. Therefore, traces of formation can still be seen in the system, such as the dust ring around the parent star. He had not yet appeared in vision five years earlier during the first observation.
All of this may seem more interesting than the chubby image might suggest at first glance. It will be many decades before images of exoplanets will resemble Google Maps. But this should not spoil the pleasure of Snellen and his colleagues around the world: “The pictures are beautiful, they show in one fell swoop that we can expect a lot from James Webb over the next twenty years.”
