TOI-2158 c
Astrophysical Synthesis & Habitability Characterization
TOI-2158 c is a confirmed gas giant exoplanet orbiting the star TOI-2158, located approximately 647.3 light-years (198.47 parsecs) from the Solar System. First announced in 2026 by Multiple Facilities using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 514.882 Earth masses (1.62 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.15 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.83 g⊕ (27.75 m/s²), and an escape velocity of 69.1 km/s.
In its orbital architecture around TOI-2158, TOI-2158 c completes one full revolution every 414.5 Earth days (1.13Julian years). The planet follows a highly eccentric trajectory (e = 0.54), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.500 R⊕, TOI-2158 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-2158 is classified as a stellar host with an effective photospheric temperature of 5,673 K, a radius of 1.32 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.619 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.7 Gyr and a metallicity of [Fe/H] = 0.47 dex (metal-rich relative to the Sun). From Earth, TOI-2158 shines at apparent V-band magnitude 10.887 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-2158 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-2158 c sharing its stellar neighborhood alongside TOI-2158 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: Multiple Facilities · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-2158 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,673 K |
| Stellar Radius | 1.3200 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.619 L☉ |
| Metallicity [Fe/H] | 0.470 dex |
| Stellar Age | 7.700 Gyr |
| Apparent Magnitude | V: 10.887 · G: 10.672 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 414.5 days |
| Orbital Eccentricity (e) | 0.54000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.15 g/cm³ (69.1 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 647.300 LY (198.473 pc) |