NASA (Exoplanet Catalog artwork)LHS 1140 b
A temperate super-Earth that may be a water world with a nitrogen atmosphere
Overview
LHS 1140 b is an exoplanet orbiting within the conservative habitable zone of the red dwarf star LHS 1140. Discovered in 2017 by the MEarth Project, LHS 1140 b is about 5.6 times the mass of Earth and about 70% larger in radius, putting it within the super-Earth category of planets. It was initially thought to be a dense rocky planet, but refined measurements of its mass and radius have found a lower density than previously estimated, indicating that it is likely an ocean planet with 9-19% of its mass composed of water. LHS 1140 b orbits entirely within the star's habitable zone and gets 43% the incident flux of Earth. The planet is 49 light-years away and transits its star, making it an excellent candidate for atmospheric studies with ground-based and/or space telescopes. Near-infrared ground-based spectroscopic observations have suggested the presence of an atmosphere containing helium. If this is true, this would be the first detection of atmosphere around a relatively rocky exoplanet in the habitable zone. However, observations with JWST have not detected any atmospheric helium.
Source: Wikipedia
NASA: LHS 1140 b is a super Earth exoplanet that orbits a M-type star. Its mass is 5.6 Earths, it takes 24.7 days to complete one orbit of its star, and is 0.0946 AU from its star. Its discovery was announced in 2017.
Why it matters
- Orbits a quiet red dwarf 48 light-years away, in the habitable zone.
- Its density points to either a snowball planet or a world with a deep global ocean.
- JWST data from 2024 gave tentative hints of a nitrogen-rich atmosphere — the best such case so far.
NASA puts it this way: “LHS 1140 b is a super Earth exoplanet that orbits an M-type star. Its mass is 6.38 Earths, it takes 24.7 days to complete one orbit of its star, and is 0.0957 AU from its star. Its discovery was announced in 2017.”
Discovery & system
- Discovered
- 2017 · Transit · MEarth Project
- Discovery paper
- Dittmann et al. 2017
- Host star
- LHS 1140 · M4.5 V · 3,096 K · 0.18 M☉
- System
- 2 known planets
- Siblings
- LHS 1140 c
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| LHS 1140 c | 3.78 d | 0.027 AU | 1.27 R⊕ | 1.91 M⊕ | 422 K |
| LHS 1140 b | 24.7 d | 0.095 AU | 1.73 R⊕ | 5.6 M⊕ | 226 K |
By the numbers
- Radius
- 1.73 R⊕11,022 km
- Mass
- 5.6 M⊕33.44 ×10²⁴ kg
- Orbital period
- 24.7 d0.07 yr
- Distance from star
- 0.095 AU14.15 million km
- Eccentricity
- 0.043nearly circular
- Equilibrium temp.
- 226 K-47 °C
- Starlight received
- 0.43 × Earth
- Distance from Earth
- 48.9 ly15 pc
- Density
- 5.9 g/cm³1.07 × 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.