A hidden hot Neptune candidate found around KIC 9139163

Star system: HD 176071 | Distance from the Sun: 335 light years

Researchers analyzed data from Kepler, TESS, and HARPS-N to study KIC 9139163, a solar-type pulsating star. They found evidence for a close-in, non-transiting planet with a mass of about 7.3 Earth masses and a radius of 2.43 Earth radii, placing it in the so-called Neptunian desert—a region where such planets are rare. The planet likely has a water-rich composition and may have lost its original hydrogen/helium envelope or developed a metal-rich atmosphere.

The study also found time-variable brightness patterns and cloud offsets in the planet’s atmosphere, with differences between the Kepler and TESS observations. These results suggest dynamic atmospheric processes and highlight the value of searching for non-transiting planets around fast-rotating stars. KIC 9139163’s planet is a promising target for future studies of hot Neptunes and their evolution.

Key findings
- A non-transiting planet candidate with 7.3 Earth masses and 2.43 Earth radii orbits KIC 9139163.
- The planet lies in the Neptunian desert and is likely water-rich.
- Atmospheric brightness and cloud patterns vary over time.
- The system is a valuable target for studying hot Neptune evolution.

Scientific study

Hidden worlds: a non-transiting candidate planet in the Neptunian desert around the solar-type pulsator KIC 9139163 (external link)