TOI-5599 b
Astrophysical Synthesis & Habitability Characterization
TOI-5599 b is a confirmed gas giant exoplanet orbiting the star TOI-5599, located approximately 1787.2 light-years (547.95 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 0.1187% across the stellar disk), this world measures 7.189 Earth radii (0.64 Jupiter radii) and has a measured mass of 40.9 Earth masses (0.13 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.79 g⊕ (7.75 m/s²), and an escape velocity of 26.7 km/s.
In its orbital architecture around TOI-5599, TOI-5599 b completes one full revolution every 5.437 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1496 K (+1223°C / +2233°F) and receiving 833.22 S⊕ (~1,134,010 W/m²), TOI-5599 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5599 is classified as a stellar host with an effective photospheric temperature of 6,137 K, a radius of 1.9133 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 4.659 L☉. From Earth, TOI-5599 shines at apparent V-band magnitude 11.779 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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-5599 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,137 K |
| Stellar Radius | 1.9133 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 4.659 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 11.779 · G: 11.648 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 5.437 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.2305° |
| Mean Bulk Density | 0.61 g/cm³ (26.7 km/s vesc) |
| Insolation Flux | 833.2180 S⊕ (~1,134,010 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1787.200 LY (547.948 pc) |