TOI-4994 b
Astrophysical Synthesis & Habitability Characterization
TOI-4994 b is a confirmed gas giant exoplanet orbiting the star TOI-4994, located approximately 1074 light-years (329.3 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 0.5509% across the stellar disk), this world measures 8.541 Earth radii (0.76 Jupiter radii) and has a measured mass of 88.992 Earth masses (0.28 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.79 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.22 g⊕ (11.96 m/s²), and an escape velocity of 36.1 km/s.
In its orbital architecture around TOI-4994, TOI-4994 b completes one full revolution every 21.492 Earth days at a semi-major axis of 0.1515 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 76.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.319, swinging from 0.1032 AU at periapsis out to 0.1998 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 718 K (+445°C / +833°F) and receiving 40.00 S⊕ (~54,440 W/m²), TOI-4994 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4994 is classified as a stellar host with an effective photospheric temperature of 5,640 K, a radius of 1.055 R☉, a mass of 1.005 M☉, an estimated bolometric luminosity of 1.01 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.3 Gyr and a metallicity of [Fe/H] = 0.165 dex (metal-rich relative to the Sun). From Earth, TOI-4994 shines at apparent V-band magnitude 12.652 (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-4994 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,640 K |
| Stellar Radius | 1.0550 R☉ |
| Stellar Mass | 1.0050 M☉ |
| Bolometric Luminosity | 1.01 L☉ |
| Metallicity [Fe/H] | 0.165 dex |
| Stellar Age | 6.300 Gyr |
| Apparent Magnitude | V: 12.652 · G: 12.479 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.151500 AU |
| Orbital Period | 21.492 days |
| Mean Orbital Velocity | 76.7 km/s |
| Orbital Eccentricity (e) | 0.31900 |
| Orbital Inclination (i) | 89.5600° |
| Mean Bulk Density | 0.79 g/cm³ (36.1 km/s vesc) |
| Insolation Flux | 40.0000 S⊕ (~54,440 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1074.000 LY (329.304 pc) |