JWST atmosphere target
LHS 1140
A super-Earth ocean world candidate — current top JWST atmosphere target.
- Planets
- 2
- Distance
- 48.9 ly
- Host
- M-type
About LHS 1140
Discovery
LHS 1140 b was discovered in 2017 by Dittmann and colleagues using the MEarth-South telescope and confirmed with HARPS radial velocities — a dense super-Earth transiting a quiet M4.5 dwarf 49 light-years away.
Why it matters
LHS 1140 b sits squarely in the habitable zone, has a measured mass and radius implying a rocky-to-water-rich composition, and orbits an unusually quiet red dwarf — together the best ingredients for atmospheric follow-up.
Current research
Cadieux et al. 2024 reported JWST/NIRISS transmission spectroscopy consistent with a nitrogen-rich atmosphere on what may be a 'water world', though the data alone cannot yet rule out a bare rock.
Comparable to
A heavier, denser Earth-cousin — 1.7 R⊕ and roughly 6 Earth masses — that may be wrapped in a global ocean.
System geometry
At a glance
- Hostname
- LHS 1140
- Spectral type
- M4.5 V
- Distance
- 48.9 ly · 14.99 pc
- Stellar mass
- 0.18 M☉
- Stellar radius
- 0.22 R☉
- Luminosity
- 3.80e-3 L☉
- Effective temp
- 3096 K
- Confirmed planets
- 2
- Habitable zone
- 0.059 – 0.084 AU
Top-down orbital diagram
Orbits to scale within this system. Dashed green = habitable-zone edges.
Planet positions are illustrative (evenly spaced in phase). For live motion see the 3D scene.
The planets
2 confirmed.
Rocky world
LHS 1140 c
- Orbit
- 0.027 AU
- Period
- 3.78 days
- Radius
- 1.27 R⊕
- Mass
- 1.91 M⊕
- Eq. temperature
- 422 K
- Eccentricity
- 0.050
- Discovered
- 2018 · Transit
Sub-Neptune
LHS 1140 b
- Orbit
- 0.095 AU
- Period
- 24.74 days
- Radius
- 1.73 R⊕
- Mass
- 5.60 M⊕
- Eq. temperature
- 226 K
- Eccentricity
- 0.043
- Discovered
- 2017 · Transit
Compared to our Solar System
Each row shows the closest Solar-System analog by radius (log-space). Earth is pinned at the bottom as the constant frame of reference.
| Planet | Radius (R⊕) | Mass (M⊕) | Orbit (AU) | Period (days) | Eq temp (K) | Solar analog |
|---|---|---|---|---|---|---|
| LHS 1140 c | 1.27 | 1.91 | 0.027 | 3.78 | 422 | Earth |
| LHS 1140 b | 1.73 | 5.60 | 0.095 | 24.74 | 226 | Earth |
| Earth (reference) | 1.00 | 1.00 | 1.000 | 365.25 | 255 | — |
Research status
◇ JWST observation status
1 planet has confirmed JWST observation time across Cycles 1–3.
- LHS 1140 b
JWST programs include transit spectroscopy, thermal phase curves, and direct imaging coronagraph observations depending on planet class.
Discovery timeline
- 2017
LHS 1140 b
via Transit
- 2018
LHS 1140 c
via Transit
If you liked this
Other systems in the same theme:
K2-18
2 planets · 124.0 ly · M2.5 V
JWST detected possible dimethyl sulfide — a potential biosignature, still debated.
WASP-39
1 planets · 697.9 ly · G2V
JWST's first CO₂ detection in an exoplanet atmosphere (2022).
GJ 1214
1 planets · 47.8 ly · M4 V
A "steam world" — hot, volatile-rich super-Earth with a hazy atmosphere.
Related reading
Articles mentioning LHS 1140:
Experience it
See LHS 1140 in interactive 3D
Fly through the system, click any planet, watch orbits play out at 100× speed.
▶ Launch 3D scene