LHS 1140 b
Astrophysical Synthesis & Habitability Characterization
LHS 1140 b 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 2017 by MEarth Project using the Transit detection technique (producing an estimated primary transit depth of 0.5397% across the stellar disk), this world measures 1.73 Earth radii and has a measured mass of 5.6 Earth masses. Combining its mass and radius yields a mean bulk density of 5.96 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.87 g⊕ (18.34 m/s²), and an escape velocity of 20.1 km/s.
In its orbital architecture around LHS 1140, LHS 1140 b completes one full revolution every 24.737 Earth days at a semi-major axis of 0.0946 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 41.6 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.043 (ranging from 0.0905 AU at periapsis to 0.0987 AU at apoapsis), the planet experiences minimal orbital distance variation.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 226 K (-47°C / -53°F) and an incident stellar irradiance of 0.43 S⊕ (~585 W/m²), LHS 1140 b orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
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 b sharing its stellar neighborhood alongside LHS 1140 c.
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: MEarth Project · 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) | 0.094600 AU |
| Orbital Period | 24.737 days |
| Mean Orbital Velocity | 41.6 km/s |
| Orbital Eccentricity (e) | 0.04300 |
| Orbital Inclination (i) | 89.8600° |
| Mean Bulk Density | 5.96 g/cm³ (20.1 km/s vesc) |
| Insolation Flux | 0.4300 S⊕ (~585 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 48.900 LY (14.986 pc) |