TOI-1533 c
Astrophysical Synthesis & Habitability Characterization
TOI-1533 c is a confirmed gas giant exoplanet orbiting the star TOI-1533, located approximately 326.3 light-years (100.05 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 0.6559% across the stellar disk), this world measures 7.5 Earth radii (0.67 Jupiter radii) and has a measured mass of 36.6 Earth masses (0.12 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.48 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.65 g⊕ (6.37 m/s²), and an escape velocity of 24.7 km/s.
In its orbital architecture around TOI-1533, TOI-1533 c completes one full revolution every 8.064 Earth days at a semi-major axis of 0.076 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 102.5 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 628 K (+355°C / +671°F) and receiving 25.90 S⊕ (~35,251 W/m²), TOI-1533 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1533 is classified as a stellar host with an effective photospheric temperature of 5,146 K, a radius of 0.849 R☉, a mass of 0.88 M☉, an estimated bolometric luminosity of 0.454 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.9 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, TOI-1533 shines at apparent V-band magnitude 10.953 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-1533 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-1533 c sharing its stellar neighborhood alongside TOI-1533 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-1533 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,146 K |
| Stellar Radius | 0.8490 R☉ |
| Stellar Mass | 0.8800 M☉ |
| Bolometric Luminosity | 0.454 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 6.900 Gyr |
| Apparent Magnitude | V: 10.953 · G: 10.682 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.076000 AU |
| Orbital Period | 8.064 days |
| Mean Orbital Velocity | 102.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.6400° |
| Mean Bulk Density | 0.48 g/cm³ (24.7 km/s vesc) |
| Insolation Flux | 25.9007 S⊕ (~35,251 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 326.300 LY (100.051 pc) |