TOI-4458 b
Astrophysical Synthesis & Habitability Characterization
TOI-4458 b is a confirmed gas giant exoplanet orbiting the star TOI-4458, located approximately 1648.5 light-years (505.43 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 0.3368% across the stellar disk), this world measures 12.408 Earth radii (1.11 Jupiter radii) and has a measured mass of 552.068 Earth masses (1.74 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.59 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.59 g⊕ (35.21 m/s²), and an escape velocity of 74.6 km/s.
In its orbital architecture around TOI-4458, TOI-4458 b completes one full revolution every 3.939 Earth days at a semi-major axis of 0.0522 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 144.2 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.03 (ranging from 0.0506 AU at periapsis to 0.0538 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1759 K (+1486°C / +2707°F) and receiving 1,595.00 S⊕ (~2,170,795 W/m²), TOI-4458 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4458 is classified as a stellar host with an effective photospheric temperature of 6,151 K, a radius of 1.96 R☉, a mass of 1.47 M☉, an estimated bolometric luminosity of 4.934 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.8 Gyr and a metallicity of [Fe/H] = 0.17 dex (metal-rich relative to the Sun). From Earth, TOI-4458 shines at apparent V-band magnitude 11.172 (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-4458 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,151 K |
| Stellar Radius | 1.9600 R☉ |
| Stellar Mass | 1.4700 M☉ |
| Bolometric Luminosity | 4.934 L☉ |
| Metallicity [Fe/H] | 0.170 dex |
| Stellar Age | 2.800 Gyr |
| Apparent Magnitude | V: 11.172 · G: 11.480 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.052200 AU |
| Orbital Period | 3.939 days |
| Mean Orbital Velocity | 144.2 km/s |
| Orbital Eccentricity (e) | 0.03000 |
| Orbital Inclination (i) | 89.4600° |
| Mean Bulk Density | 1.59 g/cm³ (74.6 km/s vesc) |
| Insolation Flux | 1595.0000 S⊕ (~2,170,795 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1648.500 LY (505.432 pc) |