TOI-7550 b
Astrophysical Synthesis & Habitability Characterization
TOI-7550 b is a confirmed sub-neptune exoplanet orbiting the star TOI-7550, located approximately 337.1 light-years (103.36 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 0.1775% across the stellar disk), this world measures 2.9 Earth radii and has a measured mass of 8.75 Earth masses. Combining its mass and radius yields a mean bulk density of 1.98 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 19.4 km/s.
In its orbital architecture around TOI-7550, TOI-7550 b completes one full revolution every 4.984 Earth days. The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 938 K (+665°C / +1229°F) and receiving 128.86 S⊕ (~175,380 W/m²), TOI-7550 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-7550 is classified as a stellar host with an effective photospheric temperature of 3,775 K, a radius of 0.6311 R☉, a mass of 0.6128 M☉, an estimated bolometric luminosity of 0.073 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.425 dex (metal-poor relative to the Sun). From Earth, TOI-7550 shines at apparent V-band magnitude 13.913 (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-7550 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,775 K |
| Stellar Radius | 0.6311 R☉ |
| Stellar Mass | 0.6128 M☉ |
| Bolometric Luminosity | 0.073 L☉ |
| Metallicity [Fe/H] | -0.425 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.913 · G: 13.126 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 4.984 days |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.98 g/cm³ (19.4 km/s vesc) |
| Insolation Flux | 128.8611 S⊕ (~175,380 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 337.100 LY (103.360 pc) |