TOI-4603 b
Astrophysical Synthesis & Habitability Characterization
TOI-4603 b is a confirmed gas giant exoplanet orbiting the star TOI-4603, located approximately 735.9 light-years (225.64 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.153% across the stellar disk), this world measures 11.68 Earth radii (1.04 Jupiter radii) and has a measured mass of 4096.808 Earth masses (12.89 Jupiter masses). Combining its mass and radius yields a mean bulk density of 14.18 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 30.03 g⊕ (294.49 m/s²), and an escape velocity of 209.5 km/s.
In its orbital architecture around TOI-4603, TOI-4603 b completes one full revolution every 7.246 Earth days at a semi-major axis of 0.0888 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 133.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.325, swinging from 0.0599 AU at periapsis out to 0.1177 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1677 K (+1404°C / +2559°F) and receiving 1,192.00 S⊕ (~1,622,312 W/m²), TOI-4603 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4603 is classified as a warm F-type star of spectral type F with an effective photospheric temperature of 6,264 K, a radius of 2.738 R☉, a mass of 1.765 M☉, an estimated bolometric luminosity of 10.355 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.64 Gyr and a metallicity of [Fe/H] = 0.342 dex (metal-rich relative to the Sun). From Earth, TOI-4603 shines at apparent V-band magnitude 9.24 (accessible to binoculars and small amateur telescopes) 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-4603 |
| Spectral Type | F |
| Effective Temp (Teff) | 6,264 K |
| Stellar Radius | 2.7380 R☉ |
| Stellar Mass | 1.7650 M☉ |
| Bolometric Luminosity | 10.355 L☉ |
| Metallicity [Fe/H] | 0.342 dex |
| Stellar Age | 1.640 Gyr |
| Apparent Magnitude | V: 9.240 · G: 9.075 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.088800 AU |
| Orbital Period | 7.246 days |
| Mean Orbital Velocity | 133.3 km/s |
| Orbital Eccentricity (e) | 0.32500 |
| Orbital Inclination (i) | 80.2100° |
| Mean Bulk Density | 14.18 g/cm³ (209.5 km/s vesc) |
| Insolation Flux | 1192.0000 S⊕ (~1,622,312 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 735.900 LY (225.643 pc) |