NASA/ESA/CSA James Webb Space Telescope has confirmed the existence of a 0.99-Earth-radius warm exoplanet inside the habitable zone LHS 475.
Artist’s impression showing LHS475b with its parent star. Image credit: NASA / ESA / CSA / Leah Hustak, STScI.
LHS 475, a M3.5-type dwarf star is located 41 light years away in the constellation Octans.
The star, also known by L 22-69 or LTT 7606, is 28% smaller than the Sun.
LHS 475 is home to at least one of the planets that were previously designated as planet candidates by NASA’s Transiting Exoplanet Survey Satellite, (TESS).
This planet, named LHS 475b and with an orbital period 2.03 days, is 99.1% larger than Earth.
It is possible that the alien world will be locked in a tidal lock, and have a dayside facing its host star.
Dr. Jacob Lustig Yaeger (an astronomer at Johns Hopkins University Applied Physics Laboratory) and his collaborators said, “We chose the LHS475 system as one among several nearby M-dwarfs with known or potential rocky planets.”
Webb’s Near-Infrared Spectrograph, (NIRSpec), captured LHS475b clearly and easily with just two transit observations.
It is clear that our planet exists. Webb’s flawless data confirm it,” Dr. Lustig Yaeger stated.
“The fact it is also a tiny, rocky planet makes it impressive for the observatory,” said Dr. Kevin Stevenson from Johns Hopkins University Applied Physics Laboratory.
Dr. Mark Clampin is the director of NASA’s Astrophysics Division.
Webb brings us closer and nearer to understanding Earth-like planets beyond our Solar System. And the mission is just beginning.
Only Webb, out of all the operating telescopes is capable of describing the atmospheres on Earth-sized exoplanets.
Astronomers used the transmission spectrum to determine what was in the atmosphere of the planet.
The data indicate that it is a terrestrial planet of Earth size, but they don’t know whether or not it has an atmosphere.
“The observatory’s data are stunning,” stated Dr. Erin May from Johns Hopkins University Applied Physics Laboratory.
The telescope detects a wide range of molecules but cannot yet determine the atmosphere.
While the authors cannot conclude what’s present, they are able to say what isn’t.
We can exclude certain terrestrial-type atmospherics. “It can’t have thick, methane-dominated atmospherics similar to Saturn’s moon Titan,” Dr. Lustig Yaeger stated.
Researchers also noted that, while the possibility exists that there is no planet’s atmosphere, some atmospheric compositions have been suggested that could be possible, including a pure carbon dioxide atmosphere.
Dr. Lustig Yaeger stated, “Counterintuitively, the 100% carbon dioxide atmosphere becomes so compact that it becomes very difficult to detect.”
Webb revealed LHS475b to be a couple hundred degrees cooler than Earth. If clouds are found, this could lead scientists to believe that the planet may look more like Venus. Venus has a constant cloud cover and a carbon dioxide atmosphere.
We are at the forefront in studying tiny, rocky exoplanets. “We have only scratched the surface of their atmospheres,” Dr. Lustig Yaeger stated.
The journal will publish the paper of the team Astronomy of Nature.
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J. Lustig-Yaeger The authors and others. 2023. The JWST spectrum for a near Earth-sized exoplanet. Astronomy of NatureIn press. arXiv: 231.04191