Follow us Add us as a preferred source on Google Newsletter Subscribe to our newsletter Sometimes science can seem really counterintuitive. For example, sometimes in astronomy you can see more with less light. Case in point: the appearance of a giant planet in observations by the James Webb Space Telescope (JWST), when astronomers found a way to block the light from the planet’s parent star. The extrasolar planet, or exoplanet, in question is 51 Eridani b (51 ERI b), a gas giant with the same mass as about 11 Jupiter orbiting a star located about 97 light years away. 51 ERI b was discovered in 2015 by ground-based telescopes, but the planet was not featured in JWST observations of the system. That was not a fault of JWST itself; No one doubts the observation capabilities of the most powerful telescope that humanity has ever placed in orbit around the Earth. Instead, it was the result of starlight from the star 51 ERI A obscuring this intimidatingly massive world. The brightest planets are 100,000 times fainter than their host stars, meaning spotting them is like watching a firefly fluttering around a lighthouse. Even using a tool called a coronagraph to block out the star isn’t enough to reveal the planet, since that doesn’t stop all the starlight. The only solution to this glaring problem is a computer program to eliminate starlight. “Over the past 20 years, astronomers have tackled this problem by looking at a different star and using its image as a reference,” Jason Wang of Northwestern University explained in a statement. “Then they subtract that reference image from the original observation to remove unwanted glare and reveal faint planets that might otherwise be hidden.” However, there is a problem with this process. Even the most stable telescopes “wobble.” For example, the JWST requires cryocoolers to keep its NIRCam instrument super cool, and those coolers have small motors that can make the mirrors vibrate. This movement, however slight, causes a scattering of starlight. The result is that enough glow remains to obscure a planet, but Wang and his colleagues developed a new approach to this problem. You may like Telescopes, their more stable digital twins The new approach taken by the team is called Physics-Based Learning for Imaging Planets (FLIP) and involves creating a digital “twin” of a telescope. Essentially, a virtual replica that simulates how starlight travels through the telescope’s mirrors and reaches its detectors. This twin is then adjusted to account for millions of tiny imperfections in the original telescope. The digital twin is then adjusted until it aligns with the real telescope’s observations. Astronomers can then remove the simulated glow from the original image. To evaluate the validity of the technique, the researchers took a second look at JWST observations of two star systems with known exoplanets, HIP 65426 and 51 Eridani, and one system, TYC 5899, with no known planets. Subtracting starlight finds hidden planet – YouTube Watch On The researchers found that in terms of detecting faint exoplanets, FLIP outperformed conventional image processing techniques by two to 15 times. This led to the emergence of ERI based on data collected by the JWST two years ago. “We’ve shown that we can bring back a planet that people couldn’t see before,” Wang said. “This is real data in a real scenario. It was science that was left on the table because we didn’t have the right tools to analyze the data in the most optimal way.” What to read next Left: JWST/NIRCam observation of the star 51 Eridani A (51 Eri) in the F430M filter, using the standard KLIP method to subtract the star’s glow. Middle: The same observation, but using the new FLIP method to subtract the star’s brightness. Right: Simulated image of 51 Eri b (Image credit: Rodrigo Ferrer-Chávez). The team hopes that other astronomers can adopt FLIP in a bid to recover hitherto undiscovered exoplanets that have been obscured by the glare of their stars. This could be a boon to NASA’s proposed Habitable Worlds Observatory, which aims to directly photograph Earth-like planets orbiting distant Sun-like stars. “We don’t know of any planets around other stars that are like those in our own solar system,” said team leader Rodrigo Ferrer-Chávez of Northwestern University. “It’s not that they don’t exist. It’s that we can’t see them.” Every time we improve our techniques, we discover new types of planets. By finding more planets, we will be able to better understand how planetary systems form and evolve and, ultimately, how typical our own solar system really is.” The team’s research was published Wednesday (Nov. 4) in the journal Nature.
