Digital Twin Exoplanet Discovery
Astronomers have used a virtual replica of the James Webb Space Telescope to reveal the hidden gas giant 51 Eridani b in existing archives, Science Daily reported.
The planet has a mass equal to roughly 11 Jupiters and orbits its parent star from about 97 light-years away, according to Space. Researchers developed a computer framework called FLIP to subtract starlight from telescope images.
Building the FLIP Framework
FLIP stands for Physics-based Learning for Imaging Planets, Ars Technica reported. The software creates a digital twin of Webb’s Near Infrared Camera, known as NIRCam.
The system applies gradient descent to optimize millions of parameters within a physical model of the instrument. That optimization accounts for tiny optical instabilities and pointing errors, according to Nature.
“Directly imaging exoplanets is incredibly challenging because even the tiniest imperfections in a telescope can make it difficult to separate the faint light of a planet from the overwhelming glare of its star,” Caltech’s Katie Bouman said in a statement reported by Science Daily.
Testing on Known Star Systems
The research team tested their software on three targets: the star systems HIP 65426, 51 Eridani, and TYC 5899, as reported by Ars Technica. Two of those systems contain young, warm exoplanets.
For TYC 5899, which has no known planets, the approach boosted observation sensitivity by a factor of 15, according to Ars Technica. Across the tests, FLIP achieved between two and 15 times greater sensitivity than conventional processing methods like KLIP.
“As you go through this iterative process of trying to find what the telescope actually is doing during observations, you basically see the glare of the star disappearing in very bizarre ways,” Rodrigo Ferrer-Chavez of Northwestern University told Science Daily.
Revisiting Webb Archives
The breakthrough means scientists can search old telescope data for worlds that slipped past earlier analysis, according to Science Daily. The technique works on data already collected by the observatory.
51 Eridani b was originally discovered in 2015 by ground-based telescopes, Space reported. The planet remained absent from earlier Webb observations partly because its atmosphere contains carbon dioxide, which absorbs infrared light near 4.3 microns, making it even fainter, according to The Daily Galaxy.
“We now have a tool that lets us discover and study planets that we were not able to ‘see’ before, even if that planet was already in an image in the JWST archive,” Ferrer-Chavez said.
Questions About Faint World Detection
How does the digital twin remove starlight?
The software simulates the Point Spread Function of the telescope optics and uses machine learning optimization tools to adjust millions of variables. It matches the simulated glare to actual observations so researchers can digitally subtract the star’s light.
Why was 51 Eridani b missing from previous Webb data?
Tiny thermal expansions and motor vibrations in Webb’s cryocoolers cause mirror movements that scatter starlight. Carbon dioxide in the planet’s atmosphere also absorbs infrared light at specific wavelengths, hiding it within the residual stellar glare.
Can this method apply to other telescopes?
The research team intends to adapt FLIP for use with ground-based observatories and NASA’s Nancy Grace Roman Space Telescope, according to Science Daily.
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