TOI-954 b
Astrophysical Synthesis & Habitability Characterization
TOI-954 b is a confirmed gas giant exoplanet orbiting the star TOI-954, located approximately 778.8 light-years (238.77 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 0.2141% across the stellar disk), this world measures 9.55 Earth radii (0.85 Jupiter radii) and has a measured mass of 55.302 Earth masses (0.17 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.35 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.61 g⊕ (5.98 m/s²), and an escape velocity of 26.9 km/s.
In its orbital architecture around TOI-954, TOI-954 b completes one full revolution every 3.685 Earth days at a semi-major axis of 0.04963 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 146.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.14 carries the world between 0.0427 AU at periapsis and 0.0566 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1526 K (+1253°C / +2287°F) and receiving 1,393.00 S⊕ (~1,895,873 W/m²), TOI-954 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-954 is classified as a stellar host with an effective photospheric temperature of 5,710 K, a radius of 1.892 R☉, a mass of 1.201 M☉, an estimated bolometric luminosity of 3.414 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.14 Gyr and a metallicity of [Fe/H] = 0.215 dex (metal-rich relative to the Sun). From Earth, TOI-954 shines at apparent V-band magnitude 10.343 (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-954 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,710 K |
| Stellar Radius | 1.8920 R☉ |
| Stellar Mass | 1.2010 M☉ |
| Bolometric Luminosity | 3.414 L☉ |
| Metallicity [Fe/H] | 0.215 dex |
| Stellar Age | 6.140 Gyr |
| Apparent Magnitude | V: 10.343 · G: 10.232 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.049630 AU |
| Orbital Period | 3.685 days |
| Mean Orbital Velocity | 146.5 km/s |
| Orbital Eccentricity (e) | 0.14000 |
| Orbital Inclination (i) | 84.4000° |
| Mean Bulk Density | 0.35 g/cm³ (26.9 km/s vesc) |
| Insolation Flux | 1393.0000 S⊕ (~1,895,873 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 778.800 LY (238.768 pc) |