TOI-5688 A b
Astrophysical Synthesis & Habitability Characterization
TOI-5688 A b is a confirmed gas giant exoplanet orbiting the star TOI-5688 A, located approximately 738.1 light-years (226.32 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 2.7445% across the stellar disk), this world measures 10.3 Earth radii (0.92 Jupiter radii) and has a measured mass of 124 Earth masses (0.39 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.63 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 38.8 km/s.
In its orbital architecture around TOI-5688 A, TOI-5688 A b completes one full revolution every 2.948 Earth days at a semi-major axis of 0.03379 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 124.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.128 carries the world between 0.0295 AU at periapsis and 0.0381 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 742 K (+469°C / +876°F) and receiving 50.30 S⊕ (~68,458 W/m²), TOI-5688 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5688 A is classified as a stellar host with an effective photospheric temperature of 3,713 K, a radius of 0.57 R☉, a mass of 0.6 M☉, an estimated bolometric luminosity of 0.055 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.2 Gyr and a metallicity of [Fe/H] = 0.47 dex (metal-rich relative to the Sun). From Earth, TOI-5688 A shines at apparent V-band magnitude 15.78 (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-5688 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,713 K |
| Stellar Radius | 0.5700 R☉ |
| Stellar Mass | 0.6000 M☉ |
| Bolometric Luminosity | 0.055 L☉ |
| Metallicity [Fe/H] | 0.470 dex |
| Stellar Age | 7.200 Gyr |
| Apparent Magnitude | V: 15.780 · G: 15.324 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.033790 AU |
| Orbital Period | 2.948 days |
| Mean Orbital Velocity | 124.7 km/s |
| Orbital Eccentricity (e) | 0.12800 |
| Orbital Inclination (i) | 87.0500° |
| Mean Bulk Density | 0.63 g/cm³ (38.8 km/s vesc) |
| Insolation Flux | 50.3000 S⊕ (~68,458 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 738.100 LY (226.318 pc) |