NASA’s James Webb Space Telescope is wobbly—scientists have a fix that could reveal new alien worlds
Scientific American · Jacek Krywko ·
By modeling the James Webb Space Telescope’s tiny movements, a new technique can reveal up to 15 times fainter alien worlds
Directly spotting a planet around another star is like trying to see the constellations at noon. Even the biggest planets can be more than 10,000 times fainter than the stars they circle, and their light gets lost in the glare. In a new Nature study, astronomers built clever software for the James Webb Space Telescope that makes this task less challenging, giving the observatory a better chance of spotting planets closer to their stars. The software has already revealed a new view of a known giant planet hidden in JWST data.
Researchers remove the majority of a star’s glare from JWST images using a mask inside the telescope called a coronagraph that blocks most of the star’s light. “It is something like an artificial eclipse,” says the study’s lead author Rodrigo Ferrer-Chavez, an astronomer at Northwestern University. A little glare still leaks through, so astronomers also image a similar “reference star” or stars and subtract the glare they measure from the new image.
But this template is a snapshot taken by the telescope at a different moment—and a telescope is never in the same state twice. Stars sit slightly off-center, temperatures shift, JWST’s 6.5-meter mirror flexes. These tiny mismatches leave smudges of starlight that can hide a faint planet in the image, meaning that the telescope’s ability to see smaller planets is limited by its overall stability.
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