TOI-4961 b
Astrophysical Synthesis & Habitability Characterization
TOI-4961 b is a confirmed gas giant exoplanet orbiting the star TOI-4961, located approximately 695 light-years (213.07 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 1.539% across the stellar disk), this world measures 12.341 Earth radii (1.1 Jupiter radii) and has a measured mass of 572.091 Earth masses (1.8 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.68 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.76 g⊕ (36.87 m/s²), and an escape velocity of 76.2 km/s.
In its orbital architecture around TOI-4961, TOI-4961 b completes one full revolution every 7.479 Earth days at a semi-major axis of 0.0726 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 105.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.182 carries the world between 0.0594 AU at periapsis and 0.0858 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 919 K (+646°C / +1195°F) and receiving 115.00 S⊕ (~156,515 W/m²), TOI-4961 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4961 is classified as a stellar host with an effective photospheric temperature of 5,380 K, a radius of 0.912 R☉, a mass of 0.912 M☉, an estimated bolometric luminosity of 0.625 L☉. Stellar evolution modeling indicates an estimated stellar age of 8 Gyr and a metallicity of [Fe/H] = 0.206 dex (metal-rich relative to the Sun). From Earth, TOI-4961 shines at apparent V-band magnitude 12.486 (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-4961 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,380 K |
| Stellar Radius | 0.9120 R☉ |
| Stellar Mass | 0.9120 M☉ |
| Bolometric Luminosity | 0.625 L☉ |
| Metallicity [Fe/H] | 0.206 dex |
| Stellar Age | 8.000 Gyr |
| Apparent Magnitude | V: 12.486 · G: 12.269 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.072600 AU |
| Orbital Period | 7.479 days |
| Mean Orbital Velocity | 105.6 km/s |
| Orbital Eccentricity (e) | 0.18200 |
| Orbital Inclination (i) | 88.1100° |
| Mean Bulk Density | 1.68 g/cm³ (76.2 km/s vesc) |
| Insolation Flux | 115.0000 S⊕ (~156,515 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 695.000 LY (213.073 pc) |