TOI-2459 b
Astrophysical Synthesis & Habitability Characterization
TOI-2459 b is a confirmed sub-neptune exoplanet orbiting the star TOI-2459, located approximately 119.4 light-years (36.61 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 0.1608% across the stellar disk), this world measures 2.953 Earth radii and has a measured mass of 9.03 Earth masses. Combining its mass and radius yields a mean bulk density of 1.93 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.6 km/s.
In its orbital architecture around TOI-2459, TOI-2459 b completes one full revolution every 19.105 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 445 K (+172°C / +342°F) and receiving 8.52 S⊕ (~11,594 W/m²), TOI-2459 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-2459 is classified as a stellar host with an effective photospheric temperature of 4,195 K, a radius of 0.6751 R☉, a mass of 0.66 M☉, an estimated bolometric luminosity of 0.127 L☉. From Earth, TOI-2459 shines at apparent V-band magnitude 10.772 (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-2459 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,195 K |
| Stellar Radius | 0.6751 R☉ |
| Stellar Mass | 0.6600 M☉ |
| Bolometric Luminosity | 0.127 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 10.772 · G: 10.165 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 19.105 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.5900° |
| Mean Bulk Density | 1.93 g/cm³ (19.6 km/s vesc) |
| Insolation Flux | 8.5187 S⊕ (~11,594 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 119.400 LY (36.611 pc) |