TOI-6716 b
Astrophysical Synthesis & Habitability Characterization
TOI-6716 b is a confirmed terrestrial exoplanet orbiting the star TOI-6716, located approximately 61.6 light-years (18.89 parsecs) from the Solar System. First announced in 2026 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1519% across the stellar disk), this world measures 0.982 Earth radii and has a measured mass of 0.911 Earth masses. Combining its mass and radius yields a mean bulk density of 5.3 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.94 g⊕ (9.22 m/s²), and an escape velocity of 10.8 km/s.
In its orbital architecture around TOI-6716, TOI-6716 b completes one full revolution every 4.719 Earth days at a semi-major axis of 0.0319 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 73.5 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.88, swinging from 0.0038 AU at periapsis out to 0.06 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 369 K (+96°C / +205°F) and receiving 4.40 S⊕ (~5,988 W/m²), TOI-6716 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-6716 is classified as a low-mass red dwarf of spectral type M4 with an effective photospheric temperature of 3,110 K, a radius of 0.231 R☉, a mass of 0.223 M☉, an estimated bolometric luminosity of 0.00448 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, TOI-6716 shines at apparent V-band magnitude 14.8 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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-6716 |
| Spectral Type | M4 |
| Effective Temp (Teff) | 3,110 K |
| Stellar Radius | 0.2310 R☉ |
| Stellar Mass | 0.2230 M☉ |
| Bolometric Luminosity | 0.00448 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.800 · G: 13.127 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.031900 AU |
| Orbital Period | 4.719 days |
| Mean Orbital Velocity | 73.5 km/s |
| Orbital Eccentricity (e) | 0.88000 |
| Orbital Inclination (i) | 89.4500° |
| Mean Bulk Density | 5.3 g/cm³ (10.8 km/s vesc) |
| Insolation Flux | 4.4000 S⊕ (~5,988 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 61.600 LY (18.887 pc) |