TOI-159 b
Astrophysical Synthesis & Habitability Characterization
TOI-159 b is a confirmed gas giant exoplanet orbiting the star TOI-159, located approximately 1133.7 light-years (347.59 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 1.0585% across the stellar disk), this world measures 18.18 Earth radii (1.62 Jupiter radii) and has a measured mass of 1110 Earth masses (3.49 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.02 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.36 g⊕ (32.95 m/s²), and an escape velocity of 87.4 km/s.
In its orbital architecture around TOI-159, TOI-159 b completes one full revolution every 3.763 Earth days at a semi-major axis of 0.056 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 161.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 0.0426 AU at periapsis and 0.0694 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1891 K (+1618°C / +2944°F) and receiving 1,797.83 S⊕ (~2,446,843 W/m²), TOI-159 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-159 is classified as a warm F-type star of spectral type F0 V with an effective photospheric temperature of 7,287 K, a radius of 1.62 R☉, a mass of 1.661 M☉, an estimated bolometric luminosity of 6.639 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.145 Gyr and a metallicity of [Fe/H] = 0.3 dex (metal-rich relative to the Sun). From Earth, TOI-159 shines at apparent V-band magnitude 11.021 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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-159 |
| Spectral Type | F0 V |
| Effective Temp (Teff) | 7,287 K |
| Stellar Radius | 1.6200 R☉ |
| Stellar Mass | 1.6610 M☉ |
| Bolometric Luminosity | 6.639 L☉ |
| Metallicity [Fe/H] | 0.300 dex |
| Stellar Age | 0.145 Gyr |
| Apparent Magnitude | V: 11.021 · G: 10.850 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.056000 AU |
| Orbital Period | 3.763 days |
| Mean Orbital Velocity | 161.9 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | 88.5000° |
| Mean Bulk Density | 1.02 g/cm³ (87.4 km/s vesc) |
| Insolation Flux | 1797.8272 S⊕ (~2,446,843 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1133.700 LY (347.593 pc) |