TOI-4559 b
Astrophysical Synthesis & Habitability Characterization
TOI-4559 b is a confirmed super-earth exoplanet orbiting the star TOI-4559, located approximately 103.2 light-years (31.64 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 0.1203% across the stellar disk), this world measures 1.415 Earth radii and has a measured mass of 2.59 Earth masses. Combining its mass and radius yields a mean bulk density of 5.04 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.29 g⊕ (12.65 m/s²), and an escape velocity of 15.1 km/s.
In its orbital architecture around TOI-4559, TOI-4559 b completes one full revolution every 3.966 Earth days at a semi-major axis of 0.0359 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 98.5 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 554 K (+281°C / +538°F) and receiving 15.77 S⊕ (~21,463 W/m²), TOI-4559 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4559 is classified as a stellar host with an effective photospheric temperature of 3,558 K, a radius of 0.374 R☉, a mass of 0.392 M☉, an estimated bolometric luminosity of 0.02 L☉. Stellar evolution modeling indicates an estimated stellar age of 7 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, TOI-4559 shines at apparent V-band magnitude 13.115 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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-4559 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,558 K |
| Stellar Radius | 0.3740 R☉ |
| Stellar Mass | 0.3920 M☉ |
| Bolometric Luminosity | 0.02 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 7.000 Gyr |
| Apparent Magnitude | V: 13.115 · G: 12.080 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.035900 AU |
| Orbital Period | 3.966 days |
| Mean Orbital Velocity | 98.5 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.6400° |
| Mean Bulk Density | 5.04 g/cm³ (15.1 km/s vesc) |
| Insolation Flux | 15.7700 S⊕ (~21,463 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 103.200 LY (31.635 pc) |