TOI-169 b
Astrophysical Synthesis & Habitability Characterization
TOI-169 b is a confirmed gas giant exoplanet orbiting the star TOI-169, located approximately 1330.2 light-years (407.84 parsecs) from the Solar System. First announced in 2020 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.7508% across the stellar disk), this world measures 12.173 Earth radii (1.09 Jupiter radii) and has a measured mass of 251.404 Earth masses (0.79 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.77 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.7 g⊕ (16.67 m/s²), and an escape velocity of 50.8 km/s.
In its orbital architecture around TOI-169, TOI-169 b completes one full revolution every 2.255 Earth days at a semi-major axis of 0.03524 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 170 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 1715 K (+1442°C / +2628°F) and receiving 1,443.00 S⊕ (~1,963,923 W/m²), TOI-169 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-169 is classified as a solar-type yellow star of spectral type G1 V with an effective photospheric temperature of 5,880 K, a radius of 1.288 R☉, a mass of 1.147 M☉, an estimated bolometric luminosity of 1.779 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.7 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, TOI-169 shines at apparent V-band magnitude 12.355 (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-169 |
| Spectral Type | G1 V |
| Effective Temp (Teff) | 5,880 K |
| Stellar Radius | 1.2880 R☉ |
| Stellar Mass | 1.1470 M☉ |
| Bolometric Luminosity | 1.779 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 4.700 Gyr |
| Apparent Magnitude | V: 12.355 · G: 12.238 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.035240 AU |
| Orbital Period | 2.255 days |
| Mean Orbital Velocity | 170 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 80.9800° |
| Mean Bulk Density | 0.77 g/cm³ (50.8 km/s vesc) |
| Insolation Flux | 1443.0000 S⊕ (~1,963,923 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1330.200 LY (407.840 pc) |