Water-dominated exoplanet orbits so close to its star that it faces imminent destruction

Astronomers have identified an exoplanet about 2.5 times Earth's size and 8.5 times its mass, composed of roughly 50% water, orbiting the star HD 176071 at just 1.5 million miles. The planet completes an orbit in 14 hours, and extreme tidal forces are driving it toward a fatal collision with its host star. It also resides in the Neptunian Desert, a region where such worlds are rarely found, yet retains a dynamic atmosphere.

The planet's discovery relied on comparing Kepler and TESS observations taken six years apart, revealing a phase shift in reflected light that indicated a moving, evolving atmosphere with dense clouds along its coldest edges. Because HD 176071 b never transits its star from Earth's perspective, it would normally remain invisible to standard detection methods, making this find particularly notable.

Its location in the Neptunian Desert is unusual, as that region typically lacks Neptune-sized worlds due to stellar radiation stripping their gaseous layers. Yet this water world retains its atmosphere despite its extreme proximity to its host star, and the tidal forces pulling it inward suggest a relatively short remaining lifespan before it is consumed.