LP 890-9 c 

LP 890-9 c (also known as SPECULOOS-2c) is a fascinating world located about 105 light-years away in the constellation Eridanus. It orbits one of the coolest stars known to host a planetary system.

Key Physical Characteristics

  • Planet Type: Terrestrial (rocky) Super-Earth.
  • Size: It is about 30% larger than Earth (1.37 times Earth’s radius).
  • Orbit: It completes a full orbit around its star in only 8.5 Earth days.
  • The Star: LP 890-9 is an ultra-cool dwarf. It is significantly smaller and colder than our Sun, which is why a planet orbiting so closely (in just 8 days) can still be in the habitable zone.

Habitability & Environment

In Lisa Kaltenegger’s research, LP 890-9 c is a high-priority target for atmospheric testing:

  • Location: It sits near the inner edge of its star’s habitable zone.
  • Energy Intake: It receives about 90% of the starlight that Earth gets from the Sun. This makes its radiation levels very similar to Earth’s, despite being much closer to its star.
  • Atmosphere: Scientists are eager to find out if it has a thin, life-friendly atmosphere or if it has turned into a hot, Venus-like world with a thick, suffocating layer of clouds.
  • Tidal Locking: Like most planets on this list, it is likely tidally locked, with a permanent day side and a permanent night side.

Scientific Significance

  • Second Best Candidate: After the TRAPPIST-1 system, LP 890-9 c is considered the second most favorable target for the James Webb Space Telescope to search for an atmosphere on a rocky planet orbiting an ultra-cool dwarf.
  • Discovery: It was discovered using the SPECULOOS project, which specifically searches for Earth-sized planets around the smallest and coolest stars in our neighborhood.
  • Testing Habitability: Kaltenegger highlights this planet as a crucial “test case.” If we find an atmosphere here, it suggests that even planets around ultra-cool stars can remain habitable for billions of years.

Published @ March 24, 2026 9:28 am