LTT 1445 A c
Astrophysical Synthesis & Habitability Characterization
LTT 1445 A c is a confirmed terrestrial exoplanet orbiting the star LTT 1445 A, located approximately 22.4 light-years (6.87 parsecs) from the Solar System. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1575% across the stellar disk), this world measures 1.147 Earth radii and has a measured mass of 1.54 Earth masses. Combining its mass and radius yields a mean bulk density of 5.63 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 13 km/s.
In its orbital architecture around LTT 1445 A, LTT 1445 A c completes one full revolution every 3.124 Earth days at a semi-major axis of 0.02661 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 92.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.223 carries the world between 0.0207 AU at periapsis and 0.0325 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 508 K (+235°C / +455°F) and receiving 10.90 S⊕ (~14,835 W/m²), LTT 1445 A c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star LTT 1445 A is classified as a low-mass red dwarf of spectral type M3.0 with an effective photospheric temperature of 3,340 K, a radius of 0.265 R☉, a mass of 0.257 M☉, an estimated bolometric luminosity of 0.00784 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.34 dex (metal-poor relative to the Sun). From Earth, LTT 1445 A shines at apparent V-band magnitude 10.59 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The LTT 1445 A system is a multi-planet architecture hosting 2 confirmed worlds, with LTT 1445 A c sharing its stellar neighborhood alongside LTT 1445 A 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | LTT 1445 A |
| Spectral Type | M3.0 |
| Effective Temp (Teff) | 3,340 K |
| Stellar Radius | 0.2650 R☉ |
| Stellar Mass | 0.2570 M☉ |
| Bolometric Luminosity | 0.00784 L☉ |
| Metallicity [Fe/H] | -0.340 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 10.590 · G: 10.047 |
| System Architecture | 3 Stars, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.026610 AU |
| Orbital Period | 3.124 days |
| Mean Orbital Velocity | 92.7 km/s |
| Orbital Eccentricity (e) | 0.22300 |
| Orbital Inclination (i) | 87.4300° |
| Mean Bulk Density | 5.63 g/cm³ (13 km/s vesc) |
| Insolation Flux | 10.9000 S⊕ (~14,835 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 22.400 LY (6.869 pc) |