TOI-771 c
Astrophysical Synthesis & Habitability Characterization
TOI-771 c 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 2025 by Paranal Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 1.5 Earth radii and has a measured mass of 2.87 Earth masses. Combining its mass and radius yields a mean bulk density of 4.69 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.28 g⊕ (12.55 m/s²), and an escape velocity of 15.5 km/s.
In its orbital architecture around TOI-771, TOI-771 c completes one full revolution every 7.61 Earth days at a semi-major axis of 0.046 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 65.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.065 carries the world between 0.043 AU at periapsis and 0.049 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 365 K (+92°C / +198°F) and receiving 3.00 S⊕ (~4,083 W/m²), TOI-771 c 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 c sharing its stellar neighborhood alongside TOI-771 b.
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: Paranal Observatory · 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) | 0.046000 AU |
| Orbital Period | 7.61 days |
| Mean Orbital Velocity | 65.8 km/s |
| Orbital Eccentricity (e) | 0.06500 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.69 g/cm³ (15.5 km/s vesc) |
| Insolation Flux | 3.0000 S⊕ (~4,083 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 82.400 LY (25.279 pc) |