TOI-1452 b is a candidate water world: a planet about 1.7 times Earth's width whose density suggests water may make up a large share of it. It orbits the brighter of two red dwarfs in a close pair about 100 light-years away, every 11.1 days, at a distance where its equilibrium temperature, set by starlight alone, is about 326 kelvin.
NASA's TESS satellite first saw it crossing its star, but the two stars are only 3.2 arcseconds apart, too close for TESS to tell which one the planet orbits. A team led by Charles Cadieux used ground-based telescopes to show the transits come from the brighter star, then measured the planet's mass with SPIRou, an infrared spectrograph on the Canada-France-Hawaii Telescope, at about 4.8 Earth masses. They reported it in 2022.
With both mass and size known, and the star's makeup measured by SPIRou as well, the team modelled the planet's interior. The best fit is a rocky core with about 18 percent iron and a water fraction of about 22 percent, though that number is uncertain: anywhere from about 9 to 43 percent fits. Earth, for comparison, is well under one percent water by mass. That makes TOI-1452 b a candidate ocean planet, though the team's own description, a rocky core with a volatile-rich envelope, leaves room for other makeups. The team pointed out that it is well placed for the James Webb Space Telescope, which can observe it almost all year round. A 2024 modelling study by a team led by Mangesh Daspute found that, if it has little or no atmosphere, it may instead have a rocky surface, and that with a thick atmosphere it might be too hot for liquid water.