TOI-2136 b
Astrophysical Synthesis & Habitability Characterization
TOI-2136 b is a confirmed sub-neptune exoplanet orbiting the star TOI-2136, located approximately 108.8 light-years (33.36 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 0.3487% across the stellar disk), this world measures 2.19 Earth radii and has a measured mass of 6.37 Earth masses. Combining its mass and radius yields a mean bulk density of 3.34 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.33 g⊕ (13.04 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around TOI-2136, TOI-2136 b completes one full revolution every 7.852 Earth days at a semi-major axis of 0.057 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 79 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 395 K (+122°C / +252°F) and receiving 4.00 S⊕ (~5,444 W/m²), TOI-2136 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-2136 is classified as a low-mass red dwarf of spectral type M4.5 V with an effective photospheric temperature of 3,342 K, a radius of 0.34 R☉, a mass of 0.34 M☉, an estimated bolometric luminosity of 0.013 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.6 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, TOI-2136 shines at apparent V-band magnitude 14.32 (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 | TOI-2136 |
| Spectral Type | M4.5 V |
| Effective Temp (Teff) | 3,342 K |
| Stellar Radius | 0.3400 R☉ |
| Stellar Mass | 0.3400 M☉ |
| Bolometric Luminosity | 0.013 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 4.600 Gyr |
| Apparent Magnitude | V: 14.320 · G: 12.964 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057000 AU |
| Orbital Period | 7.852 days |
| Mean Orbital Velocity | 79 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.4000° |
| Mean Bulk Density | 3.34 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 4.0000 S⊕ (~5,444 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 108.800 LY (33.363 pc) |