NASA (Exoplanet Catalog artwork)TRAPPIST-1b
The innermost TRAPPIST-1 planet: first rocky exoplanet with its heat measured by JWST
Overview
TRAPPIST-1b is a terrestrial, Earth-sized exoplanet orbiting around the ultra-cool red dwarf star TRAPPIST-1, located 40.7 light-years away from Earth in the constellation of Aquarius. The planet was detected using the transit method, where a planet dims the host star's light as it passes in front of it. It was first announced on May 2, 2016, and later studies were able to refine its physical parameters.
Source: Wikipedia
NASA: TRAPPIST-1 b is a super Earth exoplanet that orbits a M-type star. Its mass is 1.374 Earths, it takes 1.5 days to complete one orbit of its star, and is 0.01154 AU from its star. Its discovery was announced in 2016.
Why it matters
- JWST measured a dayside around 500 K in 2023, consistent with bare rock and no thick atmosphere.
- Later analyses allow a hazy CO2-rich atmosphere or a geologically young surface.
- A test case for whether planets around red dwarfs can keep any air at all.
NASA puts it this way: “TRAPPIST-1 b is a super Earth exoplanet that orbits an M-type star. Its mass is 1.374 Earths, it takes 1.5 days to complete one orbit of its star, and is 0.01154 AU from its star. Its discovery was announced in 2016.”
Discovery & system
- Discovered
- 2016 · Transit · La Silla Observatory
- Discovery paper
- Gillon et al. 2016
- Host star
- TRAPPIST-1 · M8.0 V · 2,566 K · 0.09 M☉
- System
- 7 known planets
- Siblings
- TRAPPIST-1 c, TRAPPIST-1 d, TRAPPIST-1 e, TRAPPIST-1 f, TRAPPIST-1 g, TRAPPIST-1 h
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| TRAPPIST-1 b | 1.51 d | 0.012 AU | 1.12 R⊕ | 1.37 M⊕ | 398 K |
| TRAPPIST-1 c | 2.42 d | 0.016 AU | 1.1 R⊕ | 1.31 M⊕ | 340 K |
| TRAPPIST-1 d | 4.05 d | 0.022 AU | 0.79 R⊕ | 0.39 M⊕ | 286 K |
| TRAPPIST-1 e | 6.1 d | 0.029 AU | 0.92 R⊕ | 0.69 M⊕ | 250 K |
| TRAPPIST-1 f | 9.21 d | 0.038 AU | 1.05 R⊕ | 1.04 M⊕ | 218 K |
| TRAPPIST-1 g | 12.4 d | 0.047 AU | 1.13 R⊕ | 1.32 M⊕ | 197 K |
| TRAPPIST-1 h | 18.8 d | 0.062 AU | 0.76 R⊕ | 0.33 M⊕ | 172 K |
By the numbers
- Radius
- 1.12 R⊕7,110 km
- Mass
- 1.37 M⊕8.21 ×10²⁴ kg
- Orbital period
- 1.51 d0 yr
- Distance from star
- 0.012 AU1.73 million km
- Eccentricity
- 0.006nearly circular
- Equilibrium temp.
- 398 K124 °C
- Starlight received
- 4 × Earth
- Distance from Earth
- 40.5 ly12.4 pc
- Density
- 5.44 g/cm³0.99 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.