LHS 475 b: the first exoplanet discovered by the James Webb Space Telescope

NASA reported that its James Webb Space Telescope discovered the existence of an exoplanet, called LHS 475 b, the first it has discovered since it began operating in space a year ago.

An exoplanet is a planet that does not orbit around the Sun, but around other stars.

The researchers said that this exoplanet is almost identical in size to Earth – 99% of its diameter – although “a few hundred degrees” hotter.

The US space agency said LHS 475 b is 41 light-years away, in the constellation Octans, which is “relatively close,” is rocky, and revolves around its star “in just two days, much faster.” than any planet in the solar system, which implies that it is much closer to that star.

“There is no doubt that the planet is there. Webb’s impeccable data validates this,” said Jacob Lustig-Yaeger, one of the heads of the research team, in a statement released Wednesday.

“These first results from observing a rocky, Earth-sized planet open the door to many future possibilities for studying the atmospheres of rocky planets with Webb,” added Mark Clampin, director of the Astrophysics Division at NASA Headquarters. in Washington DC.

“Webb is bringing us ever closer to a new understanding of Earth-like worlds outside our solar system, and the mission is just beginning,” Clampin said.

The James Webb is the only operational space telescope that can characterize the atmosphere of planets similar in size to Earth, although researchers don’t yet know if the discovered exoplanet has one, NASA reported.

In case of having it, one of the hypotheses is that it is composed exclusively of carbon dioxide.

“Counterintuitively, a 100% carbon dioxide atmosphere is much more compact, so much so that it becomes very difficult to detect,” Lustig-Yaeger said.

The researchers will have to continue studying the exoplanet to determine the nature of its possible atmosphere, which they will do in future observations during the boreal summer of this year.

“This is only the first of many discoveries it will make. (…) With this telescope, rocky exoplanets are the new frontier,” said Lustig-Yaeger.

The James Webb Space Telescope is an international project led by NASA together with the European Space Agency and the Canadian Space Agency.

It was launched from French Guiana on December 25, 2021 and was completed on January 8, 2022.