James Webb Telescope finds its first exoplanet

There’s a new heavy hitter in the hunt for planets beyond our solar system.

NASA’s James Webb Space Telescope – the next-generation observatory that has already sent back some of the clearest and most striking images of the universe – has been used to confirm the existence of an exoplanet for the first time, scientists announced Wednesday.

The planet, designated LHS 475 b, is a small, rocky world almost the same size as Earth, according to the research team led by astronomers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. The research was presented Wednesday at the 241st meeting of the American Astronomical Society in Seattle.

The exoplanet confirmation marks an important milestone for the $10 billion Webb telescope, which launched into space in December 2021 and began scientific operations less than a year ago. The finding shows how the observatory could be used to search for potentially habitable planets in the universe and to study the chemical makeup of their atmospheres.

“These first observational results from an Earth-sized, rocky planet open up many future possibilities for studying rocky planet atmospheres with Webb,” said Mark Clampin, director of the astrophysics division at NASA’s headquarters in Washington, DC. “Webb brings us closer and closer to a new understanding of Earth-like worlds outside our solar system, and the task is just getting started.”

Image: The James Webb Space Telescope separated from Arianespace's Ariane 5 rocket after launch on December 25, 2021 from Europes Spaceport at the Guyana Space Center in Kourou, French Guiana.  (NASA TV)

Image: The James Webb Space Telescope separated from Arianespace’s Ariane 5 rocket after launch on December 25, 2021 from Europes Spaceport at the Guyana Space Center in Kourou, French Guiana. (NASA TV)

The Webb telescope was able to confirm that LHS 475 b is an Earth-sized terrestrial planet, but researchers do not yet know whether the exoplanet has an atmosphere.

Astronomers used the observatory’s Near Infrared Spectrograph to closely study light from the exoplanet’s parent star. As the planet orbits in front of the star, the instrument compares starlight filtering through the planet’s atmosphere with unobstructed starlight.

This allows researchers to see if certain elements or molecules are present in an exoplanet’s atmosphere. These clues could indicate, for example, that a planet likely has a hydrogen-rich, carbon dioxide-containing or methane-dominated atmosphere.

Initial observations using Webb’s Near Infrared Spectrograph in August did not reveal any distinctive atmospheric features, according to the researchers. They said they expect to collect more data during the summer that could help them identify certain molecules in the atmosphere or determine whether the exoplanet has one.

“There are some terrestrial-type atmospheres that we can count as additional,” said Jacob Lustig-Yaeger, a postdoctoral researcher in the Applied Physics Laboratory, who led the research. “Saturn’s moon cannot have a thick, methane-dominated atmosphere like that of Titan.”

The researchers added that it is possible for LHS 475 b to have an atmosphere of pure carbon dioxide, but that this would be difficult to confirm even with the Webb telescope’s advanced instruments.

“We need very, very precise data to be able to distinguish a pure carbon dioxide atmosphere from a no atmosphere,” Lustig-Yaeger said in a statement. “A pure carbon dioxide atmosphere can be thin as on Mars, making it difficult to detect.”

The outer planet is located just 41 light-years from Earth in the constellation Octans. According to scientists, the planet orbits a red dwarf star whose temperature is less than half the sun. They found that LHS 475 b is also closer to its star than any planet in our solar system and takes just two days to complete one full orbit.

Observations by the Webb telescope also showed that the exoplanet was several hundred degrees hotter than Earth. A better understanding of its atmosphere could help astronomers characterize the planet and others like it.

“We’re at the forefront of studying small, rocky exoplanets,” Lustig-Yaeger said. “We’re barely starting to scratch the surface of what their atmospheres might be like.”

This article was originally published on NBCNews.com.

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