GJ 1252 b
Astrophysical Synthesis & Habitability Characterization
GJ 1252 b is a confirmed terrestrial exoplanet orbiting the star GJ 1252, located approximately 66.4 light-years (20.37 parsecs) from the Solar System. First announced in 2020 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0782% across the stellar disk), this world measures 1.193 Earth radii and has a measured mass of 1.32 Earth masses. Combining its mass and radius yields a mean bulk density of 4.29 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 11.8 km/s.
In its orbital architecture around GJ 1252, GJ 1252 b completes one full revolution every 0.518 Earth days at a semi-major axis of 0.00915 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 192.1 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 1090 K (+817°C / +1503°F) and receiving 233.00 S⊕ (~317,113 W/m²), GJ 1252 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 1252 is classified as a low-mass red dwarf of spectral type M3 with an effective photospheric temperature of 3,458 K, a radius of 0.391 R☉, a mass of 0.381 M☉, an estimated bolometric luminosity of 0.02 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.9 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, GJ 1252 shines at apparent V-band magnitude 12.68 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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 | GJ 1252 |
| Spectral Type | M3 |
| Effective Temp (Teff) | 3,458 K |
| Stellar Radius | 0.3910 R☉ |
| Stellar Mass | 0.3810 M☉ |
| Bolometric Luminosity | 0.02 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 3.900 Gyr |
| Apparent Magnitude | V: 12.680 · G: 11.236 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.009150 AU |
| Orbital Period | 0.518 days |
| Mean Orbital Velocity | 192.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 85.0000° |
| Mean Bulk Density | 4.29 g/cm³ (11.8 km/s vesc) |
| Insolation Flux | 233.0000 S⊕ (~317,113 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 66.400 LY (20.373 pc) |