NASA scientists have identified a previously undetected exoplanet by applying a technique rooted in Albert Einstein's theory of general relativity to archival data from the Transiting Exoplanet Survey Satellite (TESS). The discovery, announced by researchers at the University of Texas at Austin, marks a significant advancement in the methods used to find worlds beyond our solar system.
The newly confirmed planet, designated TIC 393818343 b, was not initially visible in standard TESS data analyses. The breakthrough came when the research team employed a method known as gravitational microlensing, a phenomenon predicted by Einstein's general relativity, which describes how massive objects warp the fabric of spacetime. When a foreground star passes in front of a more distant star, the gravity of the nearer object acts like a cosmic lens, bending and magnifying the light from the background star. This temporary brightening can reveal the presence of planets that would otherwise remain hidden.
In this case, the team reexamined TESS light curves — measurements of stellar brightness over time — and identified a subtle, short-lived brightening event that indicated a planet orbiting a star about 1,400 light-years from Earth. The planet is classified as a hot Jupiter, a gas giant similar in size to Jupiter but orbiting extremely close to its host star, completing one orbit in just 6.7 days. Its surface temperature is estimated to exceed 2,000 degrees Fahrenheit, making it an inhospitable world for life as we know it.
The discovery highlights the value of reanalyzing existing astronomical data with new techniques. TESS, launched in 2018, has been instrumental in identifying thousands of exoplanet candidates by detecting the slight dimming of a star's light when a planet transits in front of it. However, gravitational microlensing offers a complementary approach that can detect planets that do not transit, or that are too small or too distant from their stars to be spotted by the transit method alone.
«This planet was hiding in plain sight,» said Dr. Andrew Vanderburg, an astrophysicist at the University of Texas at Austin and lead author of the study. «We had the data all along, but we needed to look at it through the lens of Einstein's theory to see what was really there.» The research team's findings have been accepted for publication in the Astrophysical Journal Letters.
The success of this approach opens the door to potentially discovering many more exoplanets in TESS data that have been overlooked. The TESS mission has collected an enormous volume of observations, and the application of microlensing techniques could yield a new population of planets, particularly those in wide orbits or around faint stars. Such planets are often missed by traditional transit surveys but are crucial for understanding the full diversity of planetary systems in the galaxy.
Gravitational microlensing has been used for decades to detect exoplanets, but typically requires dedicated ground-based surveys that monitor millions of stars simultaneously. The new study demonstrates that space-based observatories like TESS can also contribute to microlensing discoveries, especially when data are analyzed with algorithms designed to detect the characteristic brightening signals. The team developed a specialized pipeline to search for microlensing events in TESS data, which could be applied to other missions such as the James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope.
The discovery of TIC 393818343 b also underscores the enduring relevance of Einstein's theories in modern astronomy. General relativity, first published in 1915, continues to provide the theoretical foundation for cutting-edge research, from gravitational wave detection to the study of black holes and the large-scale structure of the universe. «Einstein's insights are still guiding us to new discoveries more than a century later,» Vanderburg noted.
While TIC 393818343 b is unlikely to be a target for future habitability studies, its detection validates a powerful new tool for exoplanet hunters. The method could be particularly effective for finding planets in the so-called «habitable zone» of their stars — the region where conditions might be right for liquid water — if those planets are too small or too distant to be detected by transits. Future missions, including the European Space Agency's PLATO mission, may also benefit from incorporating microlensing analysis into their data processing pipelines.
For now, the discovery serves as a reminder that even well-studied datasets can yield surprises when examined with fresh eyes and innovative techniques. As TESS continues to scan the sky, and as new algorithms are developed, astronomers expect that many more hidden planets will come to light, each one adding a piece to the puzzle of how planetary systems form and evolve.