JWST atmosphere target
GJ 1214
A "steam world" — hot, volatile-rich super-Earth with a hazy atmosphere.
- Planets
- 1
- Distance
- 47.8 ly
- Host
- M-type
About GJ 1214
Discovery
GJ 1214 b was discovered in 2009 by the MEarth project (Charbonneau et al.), a transiting sub-Neptune around a nearby M4.5 dwarf — for years the prototypical 'mini-Neptune' for atmospheric study.
Why it matters
GJ 1214 b's atmosphere is famously flat in transmission — clouds and hazes mute all spectral features, frustrating ground- and space-based attempts to determine its composition for over a decade.
Current research
A 2023 JWST MIRI phase curve (Kempton et al., Nature) revealed a reflective, metal-rich atmosphere and confirmed thick high-altitude aerosols — the first phase curve of a sub-Neptune.
Comparable to
A scaled-down Neptune wrapped in such uniform haze that it looks like a billiard ball — about 2.7 Earth radii of mystery 48 light-years away.
System geometry
At a glance
- Hostname
- GJ 1214
- Spectral type
- M4 V
- Distance
- 47.8 ly · 14.64 pc
- Stellar mass
- 0.18 M☉
- Stellar radius
- 0.22 R☉
- Luminosity
- 3.90e-3 L☉
- Effective temp
- 3101 K
- Confirmed planets
- 1
- Habitable zone
- 0.059 – 0.086 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
1 confirmed.
Sub-Neptune
GJ 1214 b
- Orbit
- 0.015 AU
- Period
- 1.58 days
- Radius
- 2.73 R⊕
- Mass
- 8.41 M⊕
- Eq. temperature
- 567 K
- Eccentricity
- 0.006
- Discovered
- 2009 · 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 |
|---|---|---|---|---|---|---|
| GJ 1214 b | 2.73 | 8.41 | 0.015 | 1.58 | 567 | Neptune |
| 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.
- GJ 1214 b
JWST programs include transit spectroscopy, thermal phase curves, and direct imaging coronagraph observations depending on planet class.
Discovery timeline
- 2009
GJ 1214 b
via Transit
If you liked this
Other systems in the same theme:
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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).
55 Cancri
5 planets · 41.0 ly · G8 V
Hosts 55 Cancri e — a lava world JWST detected silicate atmosphere on.
Experience it
See GJ 1214 in interactive 3D
Fly through the system, click any planet, watch orbits play out at 100× speed.
▶ Launch 3D scene