Star TRAPPIST-1
TRAPPIST-1 is a cool Red dwarf star located approximately 40.7 light-years away from the Sun. As a low-mass star, it possesses about 9 percent of the Sun's mass and 12 percent of its radius, with a surface temperature of 2,400 K. With an estimated age of 7.6 billion years, the star is best known for hosting a compact system of seven rocky terrestrial planets, including TRAPPIST-1 b and TRAPPIST-1 c, which have become primary targets for atmospheric characterisation using the James Webb Space Telescope.
Frequently Asked Questions
How far is the TRAPPIST-1 system from the Sun?
The TRAPPIST-1 system is 41 light years or 12.5 parsecs from the Sun.
What galaxy is the TRAPPIST-1 star in?
The TRAPPIST-1 is in the Milky Way galaxy just like the Sun.
How many stars are in the TRAPPIST-1 system?
The TRAPPIST-1 is a single star, there are no other known stars in the system.
What type of star is the TRAPPIST-1?
The star TRAPPIST-1 is a Red dwarf star.
What temperature is star TRAPPIST-1?
The star TRAPPIST-1 has an effective temperature of 2400 K. Find out more about the temperature of stars in
Stellar guide
Class of stars Red dwarf
Red dwarfs are small, cool stars with surface temperatures of about 2,000–3,800 K, much cooler than the Sun. They usually have 8–50% of the Sun’s mass and shine very faintly, sometimes at just a tiny fraction of the Sun’s brightness. Classified mainly as spectral type M, they are the most common stars in the Milky Way, making up roughly 70–75% of its stellar population.
They fuse hydrogen slowly through the proton–proton chain and are fully convective, which allows them to use their fuel very efficiently. As a result, red dwarfs can live for tens of billions to trillions of years—far longer than the Sun. Many exoplanets orbit red dwarfs, including some in close habitable zones, though strong stellar activity can affect planetary environments.
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3. 10. 2026
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