Astronomers discover scorching water-rich planet that may be doomed to fall into its star

The planet candidate orbits the Sun-like star KIC 9139163 once every 14.5 hours. Researchers detected its signal in observations from NASA's Kepler and TESS space telescopes and later found the same pattern in measurements from the HARPS-N instrument, confirming that the signal comes from the star system rather than a nearby source.

The team estimates the object has a mass of about 7.3 times that of Earth and a radius of roughly 2.47 Earth radii, putting it between a super-Earth and a sub-Neptune in size. Its estimated density suggests a composition that could be around 50% water, placing it among so-called water worlds.

That does not mean the planet has oceans like Earth. It is exposed to extreme radiation because it orbits so close to its star.

The planet also lies deep inside the "Neptunian desert," a region close to stars where Neptune-sized planets are rarely found. Strong radiation in this zone is thought to strip planets of their lighter hydrogen and helium atmospheres. The researchers say the candidate could instead have retained a heavier, water-rich atmosphere, although another possibility is that it has only a thin atmosphere or almost none at all.

Its future may be less promising. The team's calculations indicate that the system cannot reach a stable configuration when tidal forces between the star and planet are taken into account. This suggests the planet's orbit may already be shrinking. However, the researchers found that it is currently far enough from the star to avoid being torn apart by tidal forces. The study does not estimate how quickly the orbit could decay.

Earlier, Qazinform News Agency reported that NASA launched a powerful Roman Space Telescope to explore the dark universe.