TOI-3877 b
Astrophysical Synthesis & Habitability Characterization
TOI-3877 b is a confirmed gas giant exoplanet orbiting the star TOI-3877, located approximately 1610.5 light-years (493.77 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 0.5492% across the stellar disk), this world measures 11.68 Earth radii (1.04 Jupiter radii) and has a measured mass of 99.798 Earth masses (0.31 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 0.73 g⊕ (7.16 m/s²), and an escape velocity of 32.7 km/s.
In its orbital architecture around TOI-3877, TOI-3877 b completes one full revolution every 4.124 Earth days at a semi-major axis of 0.0529 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 139.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.22 carries the world between 0.0413 AU at periapsis and 0.0645 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1445 K (+1172°C / +2142°F) and receiving 729.00 S⊕ (~992,169 W/m²), TOI-3877 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3877 is classified as a stellar host with an effective photospheric temperature of 5,731 K, a radius of 1.445 R☉, a mass of 1.16 M☉, an estimated bolometric luminosity of 2.021 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.9 Gyr and a metallicity of [Fe/H] = 0.269 dex (metal-rich relative to the Sun). From Earth, TOI-3877 shines at apparent V-band magnitude 12.215 (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-3877 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,731 K |
| Stellar Radius | 1.4450 R☉ |
| Stellar Mass | 1.1600 M☉ |
| Bolometric Luminosity | 2.021 L☉ |
| Metallicity [Fe/H] | 0.269 dex |
| Stellar Age | 5.900 Gyr |
| Apparent Magnitude | V: 12.215 · G: 12.364 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.052900 AU |
| Orbital Period | 4.124 days |
| Mean Orbital Velocity | 139.6 km/s |
| Orbital Eccentricity (e) | 0.22000 |
| Orbital Inclination (i) | 83.9700° |
| Mean Bulk Density | 0.35 g/cm³ (32.7 km/s vesc) |
| Insolation Flux | 729.0000 S⊕ (~992,169 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1610.500 LY (493.770 pc) |