GJ 536 b
Astrophysical Synthesis & Habitability Characterization
GJ 536 b is a confirmed sub-neptune exoplanet orbiting the star GJ 536, located approximately 34 light-years (10.41 parsecs) from the Solar System. First announced in 2016 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.41 Earth radii and has a measured mass of 6.37 Earth masses. Combining its mass and radius yields a mean bulk density of 2.51 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 18.2 km/s.
In its orbital architecture around GJ 536, GJ 536 b completes one full revolution every 8.709 Earth days at a semi-major axis of 0.0668 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.4 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 451 K (+178°C / +352°F) and receiving 9.90 S⊕ (~13,474 W/m²), GJ 536 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 536 is classified as a low-mass red dwarf of spectral type M1 V with an effective photospheric temperature of 3,641 K, a radius of 0.529 R☉, a mass of 0.528 M☉, an estimated bolometric luminosity of 0.044 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.2 Gyr and a metallicity of [Fe/H] = -0.08 dex (near-solar heavy-element abundance). From Earth, GJ 536 shines at apparent V-band magnitude 9.71 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The GJ 536 system is a multi-planet architecture hosting 2 confirmed worlds, with GJ 536 b sharing its stellar neighborhood alongside GJ 536 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 536 |
| Spectral Type | M1 V |
| Effective Temp (Teff) | 3,641 K |
| Stellar Radius | 0.5290 R☉ |
| Stellar Mass | 0.5280 M☉ |
| Bolometric Luminosity | 0.044 L☉ |
| Metallicity [Fe/H] | -0.080 dex |
| Stellar Age | 4.200 Gyr |
| Apparent Magnitude | V: 9.710 · G: 8.859 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.066800 AU |
| Orbital Period | 8.709 days |
| Mean Orbital Velocity | 83.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.51 g/cm³ (18.2 km/s vesc) |
| Insolation Flux | 9.9000 S⊕ (~13,474 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 34.000 LY (10.409 pc) |