GJ 3323 b
Astrophysical Synthesis & Habitability Characterization
GJ 3323 b is a confirmed terrestrial exoplanet orbiting the star GJ 3323, located approximately 17.5 light-years (5.38 parsecs) from the Solar System. First announced in 2017 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 1.23 Earth radii and has a measured mass of 2.02 Earth masses. Combining its mass and radius yields a mean bulk density of 5.99 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.34 g⊕ (13.14 m/s²), and an escape velocity of 14.3 km/s.
In its orbital architecture around GJ 3323, GJ 3323 b completes one full revolution every 5.364 Earth days at a semi-major axis of 0.03282 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 66.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.23 carries the world between 0.0253 AU at periapsis and 0.0404 AU at apoapsis, driving measurable seasonal insolation cycles.
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 290 K (+17°C / +63°F) and an incident stellar irradiance of 2.58 S⊕ (~3,511 W/m²), GJ 3323 b orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
The host star GJ 3323 is classified as a low-mass red dwarf of spectral type M4 with an effective photospheric temperature of 3,159 K, a radius of 0.119 R☉, a mass of 0.164 M☉, an estimated bolometric luminosity of 0.00127 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, GJ 3323 shines at apparent V-band magnitude 12.57 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The GJ 3323 system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 3323 b sharing its stellar neighborhood alongside GJ 3323 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 3323 |
| Spectral Type | M4 |
| Effective Temp (Teff) | 3,159 K |
| Stellar Radius | 0.1190 R☉ |
| Stellar Mass | 0.1640 M☉ |
| Bolometric Luminosity | 0.00127 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.570 · G: 10.647 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.032820 AU |
| Orbital Period | 5.364 days |
| Mean Orbital Velocity | 66.6 km/s |
| Orbital Eccentricity (e) | 0.23000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.99 g/cm³ (14.3 km/s vesc) |
| Insolation Flux | 2.5800 S⊕ (~3,511 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 17.500 LY (5.375 pc) |