TOI-4409 b
Astrophysical Synthesis & Habitability Characterization
TOI-4409 b is a confirmed gas giant exoplanet orbiting the star TOI-4409, located approximately 585.2 light-years (179.42 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 0.8975% across the stellar disk), this world measures 7.44 Earth radii (0.66 Jupiter radii) and has a measured mass of 14.938 Earth masses. Combining its mass and radius yields a mean bulk density of 0.2 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.27 g⊕ (2.65 m/s²), and an escape velocity of 15.9 km/s.
In its orbital architecture around TOI-4409, TOI-4409 b completes one full revolution every 92.492 Earth days. With a near-circular eccentricity of e = 0.036, the planet experiences minimal orbital distance variation.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 7.440 R⊕, TOI-4409 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star TOI-4409 is classified as an orange K-type star of spectral type K with an effective photospheric temperature of 4,928 K, a radius of 0.72 R☉, a mass of 0.763 M☉, an estimated bolometric luminosity of 0.274 L☉. Stellar evolution modeling indicates an estimated stellar age of 7 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, TOI-4409 shines at apparent V-band magnitude 12.691 (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-4409 |
| Spectral Type | K |
| Effective Temp (Teff) | 4,928 K |
| Stellar Radius | 0.7200 R☉ |
| Stellar Mass | 0.7630 M☉ |
| Bolometric Luminosity | 0.274 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 7.000 Gyr |
| Apparent Magnitude | V: 12.691 · G: 12.485 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 92.492 days |
| Orbital Eccentricity (e) | 0.03600 |
| Orbital Inclination (i) | 90.0000° |
| Mean Bulk Density | 0.2 g/cm³ (15.9 km/s vesc) |
| Insolation Flux | 2.0466 S⊕ (~2,785 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 585.200 LY (179.419 pc) |