TOI-1266 b
Astrophysical Synthesis & Habitability Characterization
TOI-1266 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1266, located approximately 117.5 light-years (36.01 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 0.298% across the stellar disk), this world measures 2.52 Earth radii and has a measured mass of 4.46 Earth masses. Combining its mass and radius yields a mean bulk density of 1.54 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.7 g⊕ (6.86 m/s²), and an escape velocity of 14.9 km/s.
In its orbital architecture around TOI-1266, TOI-1266 b completes one full revolution every 10.895 Earth days at a semi-major axis of 0.073 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 72.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.039 (ranging from 0.0702 AU at periapsis to 0.0758 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 415 K (+142°C / +288°F) and receiving 4.72 S⊕ (~6,424 W/m²), TOI-1266 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1266 is classified as a low-mass red dwarf of spectral type M2 with an effective photospheric temperature of 3,563 K, a radius of 0.4232 R☉, a mass of 0.437 M☉, an estimated bolometric luminosity of 0.026 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.6 Gyr and a metallicity of [Fe/H] = -0.109 dex (metal-poor relative to the Sun). From Earth, TOI-1266 shines at apparent V-band magnitude 12.941 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-1266 system is a multi-planet architecture hosting 3 confirmed worlds, with TOI-1266 b sharing its stellar neighborhood alongside TOI-1266 c, TOI-1266 d.
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-1266 |
| Spectral Type | M2 |
| Effective Temp (Teff) | 3,563 K |
| Stellar Radius | 0.4232 R☉ |
| Stellar Mass | 0.4370 M☉ |
| Bolometric Luminosity | 0.026 L☉ |
| Metallicity [Fe/H] | -0.109 dex |
| Stellar Age | 4.600 Gyr |
| Apparent Magnitude | V: 12.941 · G: 12.122 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.073000 AU |
| Orbital Period | 10.895 days |
| Mean Orbital Velocity | 72.9 km/s |
| Orbital Eccentricity (e) | 0.03900 |
| Orbital Inclination (i) | 89.1300° |
| Mean Bulk Density | 1.54 g/cm³ (14.9 km/s vesc) |
| Insolation Flux | 4.7200 S⊕ (~6,424 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 117.500 LY (36.012 pc) |