- NASA's TESS discovered a planet using gravitational microlensing for the first time
- The planet, Gaia23bra b, is a super-Jupiter orbiting far from its host star
- TESS usually finds planets close to stars, making this discovery unique
NASA's Transiting Exoplanet Survey Satellite (TESS) has made a new discovery by finding a planet in a different way than it usually does. For the first time, the mission identified a planet orbiting a distant star using ripples in space-time, instead of its usual planet-hunting method, reported NASA.
Unlike the star-hugging planets that TESS regularly discovers, the newly found planet is a super-Jupiter that orbits far from its host star.
Diana Dragomir, a professor at the University of New Mexico in Albuquerque and co-author of the study, said that when TESS launched, no one expected it to ever be capable of finding this kind of planet. She said that at 1.6 times Jupiter's mass and with a similar orbital distance, it would be extremely unlikely to find such a planet through the main detection method TESS was designed for. She added that the discovery implies there are probably other so-called microlensing planets hiding in TESS's data that researchers had not previously thought to look for.
Astronomers first found signs of the planet, named Gaia23bra b, in 2023 using the European Space Agency's now-retired Gaia space telescope. Gaia's alert system detected a star that suddenly became brighter, which can happen when a foreground star passes in front of a more distant star and magnifies its light through gravitational microlensing.
Researchers later examined archived TESS data and found that TESS had also recorded the same event.
The team's analysis, published on July 1 in The Astrophysical Journal Letters, revealed that Gaia23bra b orbits an orange dwarf star that has about 80 percent of the Sun's mass. The planet is nearly 40,000 light-years away from Earth, much farther than TESS's usual search range of about 150 light-years.
