TOI-2109 b
Astrophysical Synthesis & Habitability Characterization
TOI-2109 b is a confirmed gas giant exoplanet orbiting the star TOI-2109, located approximately 854.7 light-years (262.04 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.6645% across the stellar disk), this world measures 15.098 Earth radii (1.35 Jupiter radii) and has a measured mass of 1595.499 Earth masses (5.02 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.56 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 7 g⊕ (68.65 m/s²), and an escape velocity of 115 km/s.
In its orbital architecture around TOI-2109, TOI-2109 b completes one full revolution every 0.672 Earth days at a semi-major axis of 0.01791 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 289.7 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 3646 K (+3373°C / +6103°F) and receiving 17,880.99 S⊕ (~24,336,025 W/m²), TOI-2109 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-2109 is classified as a warm F-type star of spectral type F with an effective photospheric temperature of 6,540 K, a radius of 1.698 R☉, a mass of 1.453 M☉, an estimated bolometric luminosity of 4.732 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.77 Gyr and a metallicity of [Fe/H] = 0.068 dex (metal-rich relative to the Sun). From Earth, TOI-2109 shines at apparent V-band magnitude 10.217 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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-2109 |
| Spectral Type | F |
| Effective Temp (Teff) | 6,540 K |
| Stellar Radius | 1.6980 R☉ |
| Stellar Mass | 1.4530 M☉ |
| Bolometric Luminosity | 4.732 L☉ |
| Metallicity [Fe/H] | 0.068 dex |
| Stellar Age | 1.770 Gyr |
| Apparent Magnitude | V: 10.217 · G: 10.114 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.017910 AU |
| Orbital Period | 0.672 days |
| Mean Orbital Velocity | 289.7 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 70.7400° |
| Mean Bulk Density | 2.56 g/cm³ (115 km/s vesc) |
| Insolation Flux | 17880.9883 S⊕ (~24,336,025 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 854.700 LY (262.041 pc) |