GJ 1137 c
Astrophysical Synthesis & Habitability Characterization
GJ 1137 c is a confirmed sub-neptune exoplanet orbiting the star HD 93083, located approximately 93 light-years (28.52 parsecs) from the Solar System. First announced in 2026 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.11 Earth radii and has a measured mass of 5.12 Earth masses. Combining its mass and radius yields a mean bulk density of 3.01 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.4 km/s.
In its orbital architecture around HD 93083, GJ 1137 c completes one full revolution every 9.641 Earth days at a semi-major axis of 0.0835 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 94.2 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 769 K (+496°C / +925°F) and receiving 58.40 S⊕ (~79,482 W/m²), GJ 1137 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 93083 is classified as an orange K-type star of spectral type K2 IV-V with an effective photospheric temperature of 5,034 K, a radius of 0.837 R☉, a mass of 0.836 M☉, an estimated bolometric luminosity of 0.404 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.71 Gyr and a metallicity of [Fe/H] = 0.13 dex (metal-rich relative to the Sun). From Earth, HD 93083 shines at apparent V-band magnitude 8.3 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 93083 system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 1137 c sharing its stellar neighborhood alongside HD 93083 b.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 93083 |
| Spectral Type | K2 IV-V |
| Effective Temp (Teff) | 5,034 K |
| Stellar Radius | 0.8370 R☉ |
| Stellar Mass | 0.8360 M☉ |
| Bolometric Luminosity | 0.404 L☉ |
| Metallicity [Fe/H] | 0.130 dex |
| Stellar Age | 10.710 Gyr |
| Apparent Magnitude | V: 8.300 · G: 8.042 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.083500 AU |
| Orbital Period | 9.641 days |
| Mean Orbital Velocity | 94.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.01 g/cm³ (17.4 km/s vesc) |
| Insolation Flux | 58.4000 S⊕ (~79,482 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 93.000 LY (28.516 pc) |