LHS 1478 b
Astrophysical Synthesis & Habitability Characterization
LHS 1478 b is a confirmed terrestrial exoplanet orbiting the star LHS 1478, located approximately 59.5 light-years (18.23 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1911% across the stellar disk), this world measures 1.174 Earth radii and has a measured mass of 2.27 Earth masses. Combining its mass and radius yields a mean bulk density of 7.74 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 1.65 g⊕ (16.18 m/s²), and an escape velocity of 15.6 km/s.
In its orbital architecture around LHS 1478, LHS 1478 b completes one full revolution every 1.95 Earth days at a semi-major axis of 0.01872 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 104.5 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.038 (ranging from 0.018 AU at periapsis to 0.0194 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 597 K (+324°C / +615°F) and receiving 20.90 S⊕ (~28,445 W/m²), LHS 1478 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star LHS 1478 is classified as a low-mass red dwarf of spectral type m3 V with an effective photospheric temperature of 3,415 K, a radius of 0.2462 R☉, a mass of 0.2301 M☉, an estimated bolometric luminosity of 0.00740 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.38 dex (metal-poor relative to the Sun). From Earth, LHS 1478 shines at apparent V-band magnitude 13.304 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | LHS 1478 |
| Spectral Type | m3 V |
| Effective Temp (Teff) | 3,415 K |
| Stellar Radius | 0.2462 R☉ |
| Stellar Mass | 0.2301 M☉ |
| Bolometric Luminosity | 0.00740 L☉ |
| Metallicity [Fe/H] | -0.380 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.304 · G: 12.260 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.018720 AU |
| Orbital Period | 1.95 days |
| Mean Orbital Velocity | 104.5 km/s |
| Orbital Eccentricity (e) | 0.03800 |
| Orbital Inclination (i) | 87.6900° |
| Mean Bulk Density | 7.74 g/cm³ (15.6 km/s vesc) |
| Insolation Flux | 20.9000 S⊕ (~28,445 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 59.500 LY (18.228 pc) |