TOI-2158 b
Astrophysical Synthesis & Habitability Characterization
TOI-2158 b 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 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.4898% across the stellar disk), this world measures 10.077 Earth radii (0.9 Jupiter radii) and has a measured mass of 276.511 Earth masses (0.87 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.49 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.72 g⊕ (26.67 m/s²), and an escape velocity of 58.6 km/s.
In its orbital architecture around TOI-2158, TOI-2158 b completes one full revolution every 8.601 Earth days at a semi-major axis of 0.07 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 88.5 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.028 (ranging from 0.068 AU at periapsis to 0.072 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1173 K (+900°C / +1652°F) and receiving 215.00 S⊕ (~292,615 W/m²), TOI-2158 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
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 b sharing its stellar neighborhood alongside TOI-2158 c.
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-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) | 0.070000 AU |
| Orbital Period | 8.601 days |
| Mean Orbital Velocity | 88.5 km/s |
| Orbital Eccentricity (e) | 0.02800 |
| Orbital Inclination (i) | 85.8000° |
| Mean Bulk Density | 1.49 g/cm³ (58.6 km/s vesc) |
| Insolation Flux | 215.0000 S⊕ (~292,615 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 647.300 LY (198.473 pc) |