TRAPPIST-1e
TRAPPIST-1e, also designated as 2MASS J23062928-0502285 e, is a rocky, close-to-Earth-sized exoplanet orbiting within the habitable zone around the ultracool dwarf star TRAPPIST-1, located 40.7 light-years (12.5 parsecs; 385 trillion kilometers; 239 trillion miles) away from Earth in the constellation of Aquarius. Astronomers used the transit method to find the exoplanet, a method that measures the dimming of a star when a planet crosses in front of it.
Artist's impression of TRAPPIST-1e from 2018, depicted here as a tidally locked planet with a liquid ocean. The actual appearance of the exoplanet is currently unknown, but based on its density, it is likely not entirely covered in water. | |
| Discovery | |
|---|---|
| Discovered by | Michaël Gillon et al. |
| Discovery site | Spitzer Space Telescope |
| Discovery date | 22 February 2017 |
| Transit | |
| Orbital characteristics | |
| 0.02925±0.00025 AU | |
| Eccentricity | 0.00510±0.00058 |
| 6.101013±0.000035 d | |
| Inclination | 89.793°±0.048° |
| 108.37°±8.47° | |
| Star | TRAPPIST-1 |
| Physical characteristics | |
Mean radius | 0.920+0.013 −0.012 R🜨 |
| Mass | 0.692±0.022 M🜨 |
Mean density | 4.885+0.168 −0.182 g/cm3 |
| 0.817±0.024 g 8.01±0.24 m/s2 | |
| Temperature | Teq: 249.7±2.4 K (−23.5 °C; −10.2 °F) |
The exoplanet was one of seven discovered orbiting the star using observations from the Spitzer Space Telescope. Three of the seven (e, f, and g) are in the habitable zone or the "goldilocks zone". TRAPPIST-1e is similar to Earth's mass, radius, density, gravity, temperature, and stellar flux. It is also confirmed that TRAPPIST-1e lacks a cloud-free hydrogen-dominated atmosphere, meaning it is more likely to have a compact atmosphere like the terrestrial planets in the Solar System.
In November 2018, researchers determined that of the seven exoplanets in the multi-planetary system, TRAPPIST-1e has the best chance of being an Earth-like ocean planet, and the one most worthy of further study regarding habitability. According to the Habitable Exoplanets Catalog, TRAPPIST-1e is among the best potentially habitable exoplanets discovered.