TOI-5238 b
Astrophysical Synthesis & Habitability Characterization
TOI-5238 b is a confirmed sub-neptune exoplanet orbiting the star TOI-5238, located approximately 948 light-years (290.65 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 0.2189% across the stellar disk), this world measures 5.22 Earth radii (0.47 Jupiter radii) and has a measured mass of 23.7 Earth masses. Combining its mass and radius yields a mean bulk density of 0.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.87 g⊕ (8.53 m/s²), and an escape velocity of 23.8 km/s.
In its orbital architecture around TOI-5238, TOI-5238 b completes one full revolution every 4.872 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1042 K (+769°C / +1416°F) and receiving 195.93 S⊕ (~266,654 W/m²), TOI-5238 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5238 is classified as a stellar host with an effective photospheric temperature of 5,631 K, a radius of 1.0228 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 0.944 L☉. From Earth, TOI-5238 shines at apparent V-band magnitude 12.214 (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-5238 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,631 K |
| Stellar Radius | 1.0228 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 0.944 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 12.214 · G: 12.098 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 4.872 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.92 g/cm³ (23.8 km/s vesc) |
| Insolation Flux | 195.9250 S⊕ (~266,654 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 948.000 LY (290.646 pc) |