TOI-3976 A b
Astrophysical Synthesis & Habitability Characterization
TOI-3976 A b is a confirmed gas giant exoplanet orbiting the star TOI-3976 A, located approximately 1683.2 light-years (516.09 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.562% across the stellar disk), this world measures 12.274 Earth radii (1.1 Jupiter radii) and has a measured mass of 55.62 Earth masses (0.17 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.17 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.37 g⊕ (3.63 m/s²), and an escape velocity of 23.8 km/s.
In its orbital architecture around TOI-3976 A, TOI-3976 A b completes one full revolution every 6.608 Earth days at a semi-major axis of 0.0743 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 122.3 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 1295 K (+1022°C / +1872°F) and receiving 469.00 S⊕ (~638,309 W/m²), TOI-3976 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3976 A is classified as a stellar host with an effective photospheric temperature of 5,975 K, a radius of 1.501 R☉, a mass of 1.254 M☉, an estimated bolometric luminosity of 2.576 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.8 Gyr and a metallicity of [Fe/H] = 0.182 dex (metal-rich relative to the Sun). From Earth, TOI-3976 A shines at apparent V-band magnitude 12.403 (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-3976 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,975 K |
| Stellar Radius | 1.5010 R☉ |
| Stellar Mass | 1.2540 M☉ |
| Bolometric Luminosity | 2.576 L☉ |
| Metallicity [Fe/H] | 0.182 dex |
| Stellar Age | 3.800 Gyr |
| Apparent Magnitude | V: 12.403 · G: 12.219 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.074300 AU |
| Orbital Period | 6.608 days |
| Mean Orbital Velocity | 122.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.2800° |
| Mean Bulk Density | 0.17 g/cm³ (23.8 km/s vesc) |
| Insolation Flux | 469.0000 S⊕ (~638,309 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1683.200 LY (516.087 pc) |