TRAPPIST-1 f
Planet· orbits TRAPPIST-1
TRAPPIST-1 f — an Earth-sized planet in the habitable zone on a 9-day orbit, receiving about 37% of Earth's sunlight. Its density is a little below Earth's, consistent with a rocky world holding some water or ice. Potentially habitable in principle; no atmosphere has been confirmed and its surface has never been imaged.
Open in 3D viewSee TRAPPIST-1 f in the live, interactive 3D map
Key facts
Mass
6.21 × 10²⁴ kg
1.04 M⊕
Radius
6,658 km
1.04× wider than Earth
Surface gravity
9.34 m/s²
95% of Earth's gravity
Year
9.21 Earth days
Distance from TRAPPIST-1
5,758,022 km
Science
Physical
- Mass
- 6.21 × 10²⁴ kg · 1.04 M⊕
- Agol et al. 2021 — transit-timing variations
- Radius
- 6,658 km · 1.04× wider than Earth
- Agol et al. 2021 — transit photometry
- Density
- 5,020 kg/m³ · 5× water
- Computed from mass and radius
- Surface gravity
- 9.34 m/s² · 95% of Earth's gravity
- Computed from mass and radius
- Escape velocity
- 11.2 km/s
- Computed from mass and radius
Orbital
- Semi-major axis
- 5,758,022 km
- Real orbital elements (semi-major axis, period, eccentricity) from the NASA Exoplanet Archive; the system is shown face-on in the zone plane
- Eccentricity
- 0.01007
- Real orbital elements (semi-major axis, period, eccentricity) from the NASA Exoplanet Archive; the system is shown face-on in the zone plane
- Inclination
- 0.00 °
- Real orbital elements (semi-major axis, period, eccentricity) from the NASA Exoplanet Archive; the system is shown face-on in the zone plane
- Orbital period
- 9.2 days
- Real orbital elements (semi-major axis, period, eccentricity) from the NASA Exoplanet Archive; the system is shown face-on in the zone plane
- Perihelion
- 5,700,039 km
- Computed from the orbital elements
- Aphelion
- 5,816,005 km
- Computed from the orbital elements
- Mean orbital velocity
- 45.5 km/s
- Computed from the orbital elements
Atmosphere
- Composition
- Unknown — none confirmed. In the habitable zone by insolation, but receiving only about a third of Earth's sunlight it would need a warming atmosphere for liquid water; none has been detected.
Composition
- Bulk composition
- Likely rocky, with a density a little below Earth's that is consistent with some water or ice. Never imaged; appearance unknown.
- Surface appearance
- Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The surface shown is an artistic representation, shown only in Visual mode; Realism shows a plain spectral colour.
Radiation & temperature
- Insolation
- 0.373 S⊕ · 37% of the sunlight Earth receives
- Computed from TRAPPIST-1's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
- Equilibrium temperature
- 218 K (-55 °C)
- Computed model value (assumes no atmosphere), for ~37% of Earth's flux — not measured; the real temperature depends on an undetected atmosphere.
Discovery & history
- Discovered
- February 22, 2017
- By
- Michaël Gillon et al. (TRAPPIST / Spitzer)
- Method
- Transit detection
- Name
- Designated 'f' by its position in the system — planets are lettered inward to outward starting at 'b', so TRAPPIST-1 b is the innermost and h the outermost.
Revealed in February 2017, when a 20-day campaign by NASA's Spitzer Space Telescope with ground-based telescopes showed TRAPPIST-1 hosts seven transiting planets (Gillon et al., Nature, 2017). Its mass was later measured from the tiny timing tugs the planets exert on one another (transit-timing variations).
Images
Images from open archives · credit shown per image