LHS 1140 c
Astrophysical Synthesis & Habitability Characterization
LHS 1140 c is a confirmed super-earth exoplanet orbiting the star LHS 1140, located approximately 48.9 light-years (14.99 parsecs) from the Solar System. First announced in 2018 by Multiple Observatories using the Transit detection technique (producing an estimated primary transit depth of 0.2917% across the stellar disk), this world measures 1.272 Earth radii and has a measured mass of 1.91 Earth masses. Combining its mass and radius yields a mean bulk density of 5.12 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.18 g⊕ (11.57 m/s²), and an escape velocity of 13.7 km/s.
In its orbital architecture around LHS 1140, LHS 1140 c completes one full revolution every 3.778 Earth days at a semi-major axis of 0.027 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 77.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.05 carries the world between 0.0257 AU at periapsis and 0.0284 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 422 K (+149°C / +300°F) and receiving 5.30 S⊕ (~7,213 W/m²), LHS 1140 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star LHS 1140 is classified as a low-mass red dwarf of spectral type M4.5 V with an effective photospheric temperature of 3,096 K, a radius of 0.2159 R☉, a mass of 0.1844 M☉, an estimated bolometric luminosity of 0.00384 L☉. Stellar evolution modeling indicates an estimated stellar age of 5 Gyr and a metallicity of [Fe/H] = -0.15 dex (metal-poor relative to the Sun). From Earth, LHS 1140 shines at apparent V-band magnitude 14.15 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The LHS 1140 system is a multi-planet architecture hosting 2 confirmed worlds, with LHS 1140 c sharing its stellar neighborhood alongside LHS 1140 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | LHS 1140 |
| Spectral Type | M4.5 V |
| Effective Temp (Teff) | 3,096 K |
| Stellar Radius | 0.2159 R☉ |
| Stellar Mass | 0.1844 M☉ |
| Bolometric Luminosity | 0.00384 L☉ |
| Metallicity [Fe/H] | -0.150 dex |
| Stellar Age | 5.000 Gyr |
| Apparent Magnitude | V: 14.150 · G: 12.671 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.027000 AU |
| Orbital Period | 3.778 days |
| Mean Orbital Velocity | 77.7 km/s |
| Orbital Eccentricity (e) | 0.05000 |
| Orbital Inclination (i) | 89.8000° |
| Mean Bulk Density | 5.12 g/cm³ (13.7 km/s vesc) |
| Insolation Flux | 5.3000 S⊕ (~7,213 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 48.900 LY (14.986 pc) |