TRAPPIST-1 e is widely considered one of the most “Earth-like” exoplanets ever discovered. Located 40 light-years away, it is the fourth planet in the famous seven-planet TRAPPIST-1 system.

Key Physical Characteristics

• Planet Type: Terrestrial (rocky) world.
• Mass: It is very similar to Earth, with about 69% to 92% of Earth’s mass.
• Orbit: It completes one orbit around its ultra-cool dwarf star every 6.1 Earth days.
• Size: Its radius is about 92% of Earth’s, making it nearly a twin in size.

Habitability & Environment

In Lisa Kaltenegger’s research, TRAPPIST-1 e is a “top-tier” candidate because it sits right in the center of the habitable zone:

• Energy Intake: It receives about 66% of the starlight that Earth gets from the Sun. This puts it in a very temperate range—slightly cooler than Earth but warmer than Mars.
• Liquid Water: Of all seven planets in the system, “e” is the most likely to have liquid water oceans on its surface if it has an atmosphere to trap a bit of heat.
• Composition: Density measurements suggest it is a rocky world with a dense iron core, much like Earth, but it may actually be even “rockier” than its outer siblings.

Scientific Significance

• The Best Candidate: Many astronomers, including Kaltenegger, consider TRAPPIST-1 e the best chance for finding life similar to our own.
• Atmospheric Search: Scientists are currently looking for signs of a secondary atmosphere (one that developed after the planet formed) containing gases like carbon dioxide or nitrogen.
• Tidal Locking: While it is tidally locked (one side always faces the star), its similar-to-Earth gravity and energy levels make it a perfect candidate for climate models to see if winds can move heat to the dark side.

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Published @ March 24, 2026 9:22 am