TOI-771 b
Astrophysical Synthesis & Habitability Characterization
TOI-771 b is a confirmed super-earth exoplanet orbiting the star TOI-771, located approximately 82.4 light-years (25.28 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.2888% across the stellar disk), this world measures 1.36 Earth radii and has a measured mass of 2.47 Earth masses. Combining its mass and radius yields a mean bulk density of 5.41 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 15.1 km/s.
In its orbital architecture around TOI-771, TOI-771 b completes one full revolution every 2.326 Earth days at a semi-major axis of 0.0208 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 97.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.055 carries the world between 0.0197 AU at periapsis and 0.0219 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 543 K (+270°C / +518°F) and receiving 14.00 S⊕ (~19,054 W/m²), TOI-771 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-771 is classified as a low-mass red dwarf of spectral type M3 with an effective photospheric temperature of 3,370 K, a radius of 0.232 R☉, a mass of 0.22 M☉, an estimated bolometric luminosity of 0.00623 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.7 Gyr and a metallicity of [Fe/H] = -0.13 dex (metal-poor relative to the Sun). From Earth, TOI-771 shines at apparent V-band magnitude 14.888 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-771 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-771 b sharing its stellar neighborhood alongside TOI-771 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-771 |
| Spectral Type | M3 |
| Effective Temp (Teff) | 3,370 K |
| Stellar Radius | 0.2320 R☉ |
| Stellar Mass | 0.2200 M☉ |
| Bolometric Luminosity | 0.00623 L☉ |
| Metallicity [Fe/H] | -0.130 dex |
| Stellar Age | 6.700 Gyr |
| Apparent Magnitude | V: 14.888 · G: 13.367 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.020800 AU |
| Orbital Period | 2.326 days |
| Mean Orbital Velocity | 97.3 km/s |
| Orbital Eccentricity (e) | 0.05500 |
| Orbital Inclination (i) | 89.3000° |
| Mean Bulk Density | 5.41 g/cm³ (15.1 km/s vesc) |
| Insolation Flux | 14.0000 S⊕ (~19,054 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 82.400 LY (25.279 pc) |