TOI-3862 b
Astrophysical Synthesis & Habitability Characterization
TOI-3862 b is a confirmed sub-neptune exoplanet orbiting the star TOI-3862, located approximately 812.2 light-years (249.02 parsecs) from the Solar System. First announced in 2026 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.3037% across the stellar disk), this world measures 5.53 Earth radii (0.49 Jupiter radii) and has a measured mass of 53.7 Earth masses (0.17 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.75 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.76 g⊕ (17.26 m/s²), and an escape velocity of 34.9 km/s.
In its orbital architecture around TOI-3862, TOI-3862 b completes one full revolution every 1.557 Earth days at a semi-major axis of 0.02539 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 177.4 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0232 (ranging from 0.0248 AU at periapsis to 0.026 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1539 K (+1266°C / +2311°F) and receiving 358.84 S⊕ (~488,380 W/m²), TOI-3862 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3862 is classified as a stellar host with an effective photospheric temperature of 5,300 K, a radius of 0.92 R☉, a mass of 0.9 M☉, an estimated bolometric luminosity of 0.599 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, TOI-3862 shines at apparent V-band magnitude 12.351 (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-3862 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,300 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 0.9000 M☉ |
| Bolometric Luminosity | 0.599 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.351 · G: 12.233 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.025390 AU |
| Orbital Period | 1.557 days |
| Mean Orbital Velocity | 177.4 km/s |
| Orbital Eccentricity (e) | 0.02320 |
| Orbital Inclination (i) | 89.1500° |
| Mean Bulk Density | 1.75 g/cm³ (34.9 km/s vesc) |
| Insolation Flux | 358.8390 S⊕ (~488,380 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 812.200 LY (249.020 pc) |