TOI-4377 b
Astrophysical Synthesis & Habitability Characterization
TOI-4377 b is a confirmed gas giant exoplanet orbiting the star TOI-4377, located approximately 1486.7 light-years (455.82 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 0.1549% across the stellar disk), this world measures 15.11 Earth radii (1.35 Jupiter radii) and has a measured mass of 304.162 Earth masses (0.96 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.49 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.33 g⊕ (13.04 m/s²), and an escape velocity of 50.2 km/s.
In its orbital architecture around TOI-4377, TOI-4377 b completes one full revolution every 4.378 Earth days at a semi-major axis of 0.0579 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 143.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.045 (ranging from 0.0553 AU at periapsis to 0.0605 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1162 K (+889°C / +1632°F) and receiving 430.98 S⊕ (~586,567 W/m²), TOI-4377 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4377 is classified as a stellar host with an effective photospheric temperature of 4,974 K, a radius of 3.52 R☉, a mass of 1.36 M☉, an estimated bolometric luminosity of 6.805 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.88 Gyr and a metallicity of [Fe/H] = 0.205 dex (metal-rich relative to the Sun). From Earth, TOI-4377 shines at apparent V-band magnitude 11.707 (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-4377 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,974 K |
| Stellar Radius | 3.5200 R☉ |
| Stellar Mass | 1.3600 M☉ |
| Bolometric Luminosity | 6.805 L☉ |
| Metallicity [Fe/H] | 0.205 dex |
| Stellar Age | 3.880 Gyr |
| Apparent Magnitude | V: 11.707 · G: 11.457 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057900 AU |
| Orbital Period | 4.378 days |
| Mean Orbital Velocity | 143.9 km/s |
| Orbital Eccentricity (e) | 0.04500 |
| Orbital Inclination (i) | 80.3000° |
| Mean Bulk Density | 0.49 g/cm³ (50.2 km/s vesc) |
| Insolation Flux | 430.9826 S⊕ (~586,567 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1486.700 LY (455.820 pc) |