TOI-1386 c
Astrophysical Synthesis & Habitability Characterization
TOI-1386 c is a confirmed gas giant exoplanet orbiting the star TOI-1386, located approximately 479 light-years (146.86 parsecs) from the Solar System. First announced in 2024 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 10.3 Earth radii (0.92 Jupiter radii) and has a measured mass of 75.2 Earth masses (0.24 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.38 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.71 g⊕ (6.96 m/s²), and an escape velocity of 30.2 km/s.
In its orbital architecture around TOI-1386, TOI-1386 c completes one full revolution every 232 Earth days at a semi-major axis of 0.75 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 35.2 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.38, swinging from 0.465 AU at periapsis out to 1.035 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 10.300 R⊕, TOI-1386 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star TOI-1386 is classified as a solar-type yellow star of spectral type G5V with an effective photospheric temperature of 5,735 K, a radius of 1.0235 R☉, a mass of 1.0363 M☉, an estimated bolometric luminosity of 1.017 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = 0.149 dex (metal-rich relative to the Sun). From Earth, TOI-1386 shines at apparent V-band magnitude 10.61 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-1386 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-1386 c sharing its stellar neighborhood alongside TOI-1386 b.
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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-1386 |
| Spectral Type | G5V |
| Effective Temp (Teff) | 5,735 K |
| Stellar Radius | 1.0235 R☉ |
| Stellar Mass | 1.0363 M☉ |
| Bolometric Luminosity | 1.017 L☉ |
| Metallicity [Fe/H] | 0.149 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 10.610 · G: 10.507 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.750000 AU |
| Orbital Period | 232 days |
| Mean Orbital Velocity | 35.2 km/s |
| Orbital Eccentricity (e) | 0.38000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.38 g/cm³ (30.2 km/s vesc) |
| Insolation Flux | 1.7710 S⊕ (~2,410 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 479.000 LY (146.858 pc) |