Star with 7 known planets

TRAPPIST-1

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TRAPPIST-1, an M8.0 V star, has 7 confirmed planets.

Measured

Distance: about 40.5 light-years
Star's spectral type: M8.0 V
Confirmed planets: 7

How far, from the Sun

About 40.5 light-years. To cross it:

Light40.5 years
Voyager 1's speed720,000 years
Driving at 100 km/h437 million years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Facts

TRAPPIST-1 d, TRAPPIST-1 e have an equilibrium temperature between −50 and +50 °C.

How it was found

First planet found in 2016, by transit (NASA Exoplanet Archive).

Its planets

TRAPPIST-1 b — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 36 hours; about 130 °C, hotter than boiling water; found in 2016 by transit.
TRAPPIST-1 c — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 2 days; about 67 °C, between freezing and boiling; found in 2016 by transit.
TRAPPIST-1 d — 0.8 times Earth's width, smaller than the Earth; its year lasts 4 days; about 13 °C, between freezing and boiling; found in 2016 by transit.
TRAPPIST-1 e — 0.9 times Earth's width, about Earth-sized — probably rocky; its year lasts 6 days; about −23 °C, below freezing; found in 2017 by transit.
TRAPPIST-1 f — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 9 days; about −55 °C, below freezing; found in 2017 by transit.
TRAPPIST-1 g — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 12 days; about −76 °C, below freezing; found in 2017 by transit.
TRAPPIST-1 h — 0.8 times Earth's width, smaller than the Earth; its year lasts 19 days; about −100 °C, below freezing; found in 2017 by transit.

The NASA Exoplanet Archive's page

Where this comes from

NASA Exoplanet Archive, Planetary Systems Composite Parameters (fetched 2026-11-02). Composite values: where a planet's size or mass was not measured, the archive estimates it from the other.
This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.

Every catalogue Ouranos draws is credited on the credits page.

Its planets

TRAPPIST-1 b — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 36 hours; about 130 °C, hotter than boiling water; found in 2016 by transit.

TRAPPIST-1 c — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 2 days; about 67 °C, between freezing and boiling; found in 2016 by transit.

TRAPPIST-1 d — 0.8 times Earth's width, smaller than the Earth; its year lasts 4 days; about 13 °C, between freezing and boiling; found in 2016 by transit.

TRAPPIST-1 e — 0.9 times Earth's width, about Earth-sized — probably rocky; its year lasts 6 days; about −23 °C, below freezing; found in 2017 by transit.

TRAPPIST-1 f — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 9 days; about −55 °C, below freezing; found in 2017 by transit.

TRAPPIST-1 g — 1.1 times Earth's width, about Earth-sized — probably rocky; its year lasts 12 days; about −76 °C, below freezing; found in 2017 by transit.

TRAPPIST-1 h — 0.8 times Earth's width, smaller than the Earth; its year lasts 19 days; about −100 °C, below freezing; found in 2017 by transit.

Where this comes from

NASA Exoplanet Archive, Planetary Systems Composite Parameters (fetched 2026-11-02). Composite values: where a planet's size or mass was not measured, the archive estimates it from the other.

This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.

Every catalogue Ouranos draws is credited on the credits page.