Discovery of exoplanet by James Webb Space Telescope was a ‘lucky accident,' researcher says

The James Webb Space Telescope has uncovered wondrous imagery and reached numerous milestones with the latest achievement arguably its most important.

On Jan. 11, NASA confirmed that researchers have found an exoplanet, a planet outside of our solar system orbiting another star, using the Webb telescope.

Formally classified as LHS 475 b, the size of the exoplanet has intrigued many, as it is nearly the same size as Earth. LHS 475 b was noted as 99% the size of Earth's diameter and was also stated to be a rocky planet, like Earth or Mars, not a gas giant, such as Jupiter or Saturn.

NASA technicians lift mirror of the James Webb Space Telescope using a crane

In this April 13, 2017 photo provided by NASA, technicians lift the mirror of the James Webb Space Telescope using a crane at the Goddard Space Flight Center in Greenbelt, Md. (Laura Betz/NASA via AP, File)

Over 5,000 exoplanets have been confirmed by previous data, but LHS 475 b is the first to be confirmed by observations with the telescope. The exoplanet was stated to be 41 light-years away in the constellation Octans.

"These first observational results from an Earth-size, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb," said NASA Headquarters Astrophysics Division director Mark Clampin. "Webb is bringing us closer and closer to a new understanding of Earth-like worlds outside our solar system, and the mission is only getting started."

"We believe it is basically the same composition as Earth," said Guangwei Fu from the Department of Physics and Astronomy at John Hopkins University on a recent episode of AccuWeather's Everything Under The Sun podcast. "Given the same radius, it's really hard to have a different composition."

Fu pointed out that while the exoplanet's composition may be similar to Earth's, the difference is in the temperature of the exoplanet. LHS 475 b was noted to be between 500 and 600 degrees Kelvin (440 and 620 degrees Fahrenheit) compared to Earth's 280 Kelvin (44 Fahrenheit). The temperature difference may lead to a conclusion that the planet is like Venus if LHS 475 b is found to have clouds. Venus has a toxic atmosphere made of carbon dioxide which traps heat from the sun like a greenhouse, making it the hottest planet in our solar system.

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"We're at the forefront of studying small, rocky exoplanets," said Jacob Lustig-Yaeger, one of the leaders of the LHS 475 b research team. "We have barely begun scratching the surface of what their atmospheres might be like."

Researchers used NASA's James Webb Space Telescope's Near-Infrared Spectrograph (NIRSpec) to observe exoplanet LHS 475 b on August 31, 2022. (Illustration provided by NASA, ESA, CSA, L. Hustak (STScI); Science: K. Stevenson, J. Lustig-Yaeger, E. May (Johns Hopkins University Applied Physics Laboratory), G. Fu (Johns Hopkins University), and S. Moran (University of Arizona))

The Webb telescope is the only operating telescope that is capable of characterizing the atmosphere of Earth-sized exoplanets. Attempts to assess LHS 475 b's atmosphere have been made by analyzing its transmission spectrum, captured by Webb's NIRSpec instrument on Aug. 31, 2022. It is currently unknown whether the exoplanet has an atmosphere or what that atmosphere would consist of, but certain types of atmospheres have been ruled out, such as a methane-dominated atmosphere similar to Saturn's moon Titan.

Fu described the confirmation of LHS 475 b by Webb as a "lucky accident," something that wasn't the primary designation for the telescope. "I remember I was watching the launch, I stayed up all night ... it was definitely a very anxious time," Fu said. "Then there was the six-month deployment (and) testing. Now, we (have) the actual science data down, the telescope's working beautifully and data quality is very high so far."

Since launching on Dec. 25, 2021, the James Webb Space Telescope has reported several important discoveries, including the confirmation of light from galaxies that date back to less than 400 million years after the big bang. Now with the confirmation of the exoplanet, research has opened the possibility of finding Earth-sized planets that orbit smaller red dwarf stars, with Lustig-Yaeger stating that "rocky exoplanets are the new frontier." Upcoming observations on the exoplanet using the Webb are scheduled for this summer.

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