TESS finds 27 exoplanet candidates

NASA’s Transiting Exoplanet Survey Satellite, or TESS, has added a new set of possible worlds by looking not for transits, but for timing changes in binary stars’ eclipses. A NASA visualization page released on May 12 said astronomers identified 27 candidate circumbinary planets — planets orbiting two stars — after studying 1,590 eclipsing binaries with at least two years of TESS data. (svs.gsfc.nasa.gov) The underlying paper, accepted in March, said the signal came from apsidal precession, a gradual rotation of the binary orbit that can point to an unseen gravitational perturber. (arxiv.org) The result matters because most known circumbinary planets have been found only when their orbits line up just right for transits. The new method is designed to find systems that standard transit searches can miss, according to NASA and the paper’s authors. The candidates are not yet confirmed planets, and the authors said their present properties remain uncertain. ### Why were these planets hard to find in the first place? TESS has discovered 885 confirmed exoplanets and identified more than 7,900 candidates, with nearly all of them found because they pass in front of their host stars from Earth’s point of view, NASA said. (svs.gsfc.nasa.gov) That geometry works poorly in binary systems, where two stars orbit each other and the viewing angle for planetary transits can be unfavorable or unstable. Before this study, NASA said Kepler and other facilities had recorded 16 transiting worlds around binary stars, and TESS had found two more. (svs.gsfc.nasa.gov) The paper said confirmed circumbinary systems remain underrepresented because transit-based searches favor nearly coplanar systems. ### What exactly did the researchers measure? The researchers looked at eclipsing binaries, where the two stars alternately pass in front of each other. NASA said astronomers can detect the gravitational pull of an exoplanet in these systems by measuring the exact timing of many eclipses. (svs.gsfc.nasa.gov) The paper said the team searched for apsidal precession that could not be explained by general relativity, tides or stellar rotation alone. In the authors’ interpretation, excess precession signals point to an additional body in the system, allowing limits to be placed on the mass and orbital distance of a possible companion. (svs.gsfc.nasa.gov) ### What did they actually find in the TESS data? The study examined 1,590 eclipsing binaries drawn from the Gaia DR3 Catalogue of Eclipsing Binary Candidates, the paper said. From that sample, the authors reported 27 candidate circumbinary planets and six additional candidate companions with higher minimum masses. (svs.gsfc.nasa.gov) NASA’s summary described the result as “more than two dozen” candidate exoplanets and said the method lets TESS locate planets it could not otherwise detect. Universe Today, summarizing the same paper, said the physical properties of the candidates remain inconclusive. (arxiv.org) ### Are these confirmed planets yet? The 27 objects are still candidates, not confirmed planets. The paper said the same dynamical signature could come from a lower-mass planet inside 1 astronomical unit or a more massive companion on a wider orbit of a few AU, leaving a mass-distance degeneracy that the current data cannot resolve. (arxiv.org) NASA said the 27 systems now await confirmation. The authors said radial-velocity measurements can help break the degeneracy and provide direct confirmation. ### What happens next? (svs.gsfc.nasa.gov) The paper names radial-velocity follow-up as the next step, because spectroscopy can test whether the eclipse-timing signal is really caused by a planet and can better constrain mass and orbit. The candidate list comes from a study accepted on March 11, 2026, by authors including Margo Thornton, Benjamin T. Montet, Riley White, Arden Shao and Diya T. Kumar. (arxiv.org) NASA’s TESS mission page said the telescope was launched in April 2018 and continues to survey bright nearby stars. For these 27 systems, the next milestone is confirmation work on individual binaries rather than a new TESS detection count. (svs.gsfc.nasa.gov) (exoplanetarchive.ipac.caltech.edu) (arxiv.org)