TOI-4504 b
Astrophysical Synthesis & Habitability Characterization
TOI-4504 b is a confirmed sub-neptune exoplanet orbiting the star TOI-4504, located approximately 1117.4 light-years (342.61 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 0.0682% across the stellar disk), this world measures 2.65 Earth radii and has a measured mass of 140 Earth masses (0.44 Jupiter masses). Combining its mass and radius yields a mean bulk density of 41.48 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 19.94 g⊕ (195.54 m/s²), and an escape velocity of 81.3 km/s.
In its orbital architecture around TOI-4504, TOI-4504 b completes one full revolution every 2.426 Earth days at a semi-major axis of 0.0338 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 151.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.84, swinging from 0.0054 AU at periapsis out to 0.0622 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1345 K (+1072°C / +1962°F) and receiving 548.05 S⊕ (~745,902 W/m²), TOI-4504 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4504 is classified as an orange K-type star of spectral type K1 V with an effective photospheric temperature of 5,315 K, a radius of 0.93 R☉, a mass of 0.875 M☉, an estimated bolometric luminosity of 0.619 L☉. Stellar evolution modeling indicates an estimated stellar age of 10 Gyr and a metallicity of [Fe/H] = 0.16 dex (metal-rich relative to the Sun). From Earth, TOI-4504 shines at apparent V-band magnitude 13.364 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-4504 system is a multi-planet architecture hosting 3 confirmed worlds, with TOI-4504 b sharing its stellar neighborhood alongside TOI-4504 d, TOI-4504 c.
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-4504 |
| Spectral Type | K1 V |
| Effective Temp (Teff) | 5,315 K |
| Stellar Radius | 0.9300 R☉ |
| Stellar Mass | 0.8750 M☉ |
| Bolometric Luminosity | 0.619 L☉ |
| Metallicity [Fe/H] | 0.160 dex |
| Stellar Age | 10.000 Gyr |
| Apparent Magnitude | V: 13.364 · G: 13.128 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.033800 AU |
| Orbital Period | 2.426 days |
| Mean Orbital Velocity | 151.6 km/s |
| Orbital Eccentricity (e) | 0.84000 |
| Orbital Inclination (i) | 92.4000° |
| Mean Bulk Density | 41.48 g/cm³ (81.3 km/s vesc) |
| Insolation Flux | 548.0544 S⊕ (~745,902 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1117.400 LY (342.605 pc) |