TOI-712 d
Astrophysical Synthesis & Habitability Characterization
TOI-712 d is a confirmed sub-neptune exoplanet orbiting the star TOI-712, located approximately 191.2 light-years (58.62 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 0.1132% across the stellar disk), this world measures 2.474 Earth radii and has a measured mass of 6.68 Earth masses. Combining its mass and radius yields a mean bulk density of 2.43 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.09 g⊕ (10.69 m/s²), and an escape velocity of 18.4 km/s.
In its orbital architecture around TOI-712, TOI-712 d completes one full revolution every 84.84 Earth days at a semi-major axis of 0.3405 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 43.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.073 carries the world between 0.3156 AU at periapsis and 0.3654 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.474 R⊕, TOI-712 d exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star TOI-712 is classified as an orange K-type star of spectral type K4.5 V with an effective photospheric temperature of 4,622 K, a radius of 0.674 R☉, a mass of 0.732 M☉, an estimated bolometric luminosity of 0.186 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.83 Gyr and a metallicity of [Fe/H] = -0.02 dex (near-solar heavy-element abundance). From Earth, TOI-712 shines at apparent V-band magnitude 10.838 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-712 system is a multi-planet architecture hosting 3 confirmed worlds, with TOI-712 d sharing its stellar neighborhood alongside TOI-712 b, TOI-712 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-712 |
| Spectral Type | K4.5 V |
| Effective Temp (Teff) | 4,622 K |
| Stellar Radius | 0.6740 R☉ |
| Stellar Mass | 0.7320 M☉ |
| Bolometric Luminosity | 0.186 L☉ |
| Metallicity [Fe/H] | -0.020 dex |
| Stellar Age | 0.830 Gyr |
| Apparent Magnitude | V: 10.838 · G: 10.579 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.340500 AU |
| Orbital Period | 84.84 days |
| Mean Orbital Velocity | 43.7 km/s |
| Orbital Eccentricity (e) | 0.07300 |
| Orbital Inclination (i) | 89.8170° |
| Mean Bulk Density | 2.43 g/cm³ (18.4 km/s vesc) |
| Insolation Flux | 1.6000 S⊕ (~2,178 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 191.200 LY (58.621 pc) |