10,000 new planets found hidden in NASA telescope data

Artist's impression of a star with two planets transiting across it — An artist’s impression of a star with two planets transiting across it

NASA, ESA, and G. Bacon (STScI)

Astronomers have discovered over 10,000 potential planets using data from a NASA telescope, marking the largest single discovery of its kind.

Launched in 2018, NASA’s Transiting Exoplanet Survey Satellite (TESS) is designed to search the sky for orbiting planets, called exoplanets. It detects these planets by observing slight decreases in the brightness of light from stars, indicating an exoplanet has passed in front of them.

To date, the telescope has confirmed the existence of more than 750 exoplanets, while numerous other candidates await confirmation. Other telescopes have also contributed to the discovery, raising the total confirmed exoplanets by all telescopes to over 6000.

Joshua Roth from Princeton University and his team have reported a significantly larger number of potential exoplanets through a re-analysis of TESS’s first-year data. By merging images captured by the telescope, they were able to explore stars that are dimmer, either due to their smaller size or greater distance from Earth, revealing 11,554 candidate exoplanets, 10,091 of which had not been detected in previous searches.

“There have been predictions that there were thousands of planets still lurking in the TESS data,” says Roth. “It just hadn’t been searched yet.”

These planets extend up to 6800 light-years from Earth, reaching towards the center of our galaxy, doubling TESS’s previous search range. Over 90% of these new planets are hot Jupiters, which are gas giants that orbit very close to their star, completing one orbit in just a few days. TESS is particularly adept at discovering such planets. A smaller percentage are Neptunes and super-Earths.

However, not all candidates will be confirmed as real planets; each must be independently verified by other telescopes. Some might be false positives, such as binary stars or other data anomalies. “TESS usually has a false positive rate of 50 per cent,” says Roth. “I would say a maximum of 5000 are real planets,” and possibly just 3000 are, he says.

Even then, this discovery would increase the known number of exoplanets in the universe by half. Jessie Christiansen, chief scientist of the NASA Exoplanet Science Institute, notes that this will provide valuable insights into the formation and distribution of exoplanets. “I want as many exoplanets as possible so that I can start slicing and dicing things,” she says. “How are they different? What kinds of different Jupiters do different stars make? These are all questions you can ask when you have a big sample.”

Many more planets remain to be discovered in the TESS data, including about 8000 other candidate worlds identified in prior investigations that still require examination. “We were always expecting that thousands would start flooding through at some point,” says Christiansen, with forecasts indicating TESS should find 12,000 to 15,000 confirmed planets in total. “I’ve been waiting for papers like this for a long time now.”

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