TOI-1669 c
Astrophysical Synthesis & Habitability Characterization
TOI-1669 c is a confirmed sub-neptune exoplanet orbiting the star TOI-1669, located approximately 362.9 light-years (111.28 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 0.0397% across the stellar disk), this world measures 2.296 Earth radii and has a measured mass of 13 Earth masses. Combining its mass and radius yields a mean bulk density of 5.92 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 2.47 g⊕ (24.22 m/s²), and an escape velocity of 26.6 km/s.
In its orbital architecture around TOI-1669, TOI-1669 c completes one full revolution every 2.68 Earth days at a semi-major axis of 0.0376 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 152.6 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1285 K (+1012°C / +1854°F) and receiving 343.00 S⊕ (~466,819 W/m²), TOI-1669 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1669 is classified as a stellar host with an effective photospheric temperature of 5,497 K, a radius of 1.0561 R☉, a mass of 0.9867 M☉, an estimated bolometric luminosity of 0.914 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.7 Gyr and a metallicity of [Fe/H] = 0.274 dex (metal-rich relative to the Sun). From Earth, TOI-1669 shines at apparent V-band magnitude 10.218 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-1669 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-1669 c sharing its stellar neighborhood alongside TOI-1669 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-1669 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,497 K |
| Stellar Radius | 1.0561 R☉ |
| Stellar Mass | 0.9867 M☉ |
| Bolometric Luminosity | 0.914 L☉ |
| Metallicity [Fe/H] | 0.274 dex |
| Stellar Age | 7.700 Gyr |
| Apparent Magnitude | V: 10.218 · G: 10.009 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.037600 AU |
| Orbital Period | 2.68 days |
| Mean Orbital Velocity | 152.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.92 g/cm³ (26.6 km/s vesc) |
| Insolation Flux | 342.9970 S⊕ (~466,819 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 362.900 LY (111.276 pc) |