Kepler-296 f is the outer sibling of Kepler-296 e, located in the same system approximately 737 light-years away. While planet “e” is a warmer candidate, planet “f” is a colder, more distant world.

Key Physical Characteristics

• Planet Type: Terrestrial (rocky) Super-Earth.
• Size: It is about 1.75 times the radius of Earth, making it slightly larger than its inner sibling.
• Orbit: It takes about 63 Earth days to complete one orbit around its red dwarf star.
• The Star: Kepler-296 is a cool red dwarf star. Because the star is so much dimmer than our Sun, a 63-day orbit puts the planet at the outer reaches of the habitable zone.

Habitability & Environment

In Lisa Kaltenegger’s research, Kepler-296 f is often modeled as a “Cold Earth” or an “Ice World”:

• Location: It sits on the outer edge of the habitable zone.
• Energy Intake: It receives only about one-third (34%) of the starlight that Earth gets from the Sun. This is very similar to the amount of energy Mars receives in our solar system.
• Atmosphere: To have liquid water on its surface, Kepler-296 f would need a very thick atmosphere with strong greenhouse gases (like CO2) to trap enough heat. Without such an atmosphere, it would likely be a frozen, icy desert.

Scientific Significance

• The “Double” Target: Having two planets (e and f) in the same habitable zone allows scientists to study the “inner” and “outer” limits of life’s potential in a single system.
• Composition: Because of its size, it sits near the boundary where planets transition from being rocky to being gaseous “mini-Neptunes.” Models suggest that if it is rocky, it could be a “Water World” with deep global oceans covered by ice.
• Discovery: It was discovered by the Kepler Space Telescope using the transit method, where the planet’s passage in front of the star causes a tiny dip in brightness.

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Published @ March 24, 2026 9:36 am