TOI-5777 b
Astrophysical Synthesis & Habitability Characterization
TOI-5777 b is a confirmed sub-neptune exoplanet orbiting the star TOI-5777, located approximately 372.7 light-years (114.28 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 0.1785% across the stellar disk), this world measures 3.096 Earth radii (0.28 Jupiter radii) and has a measured mass of 9.78 Earth masses. Combining its mass and radius yields a mean bulk density of 1.82 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.02 g⊕ (10 m/s²), and an escape velocity of 19.9 km/s.
In its orbital architecture around TOI-5777, TOI-5777 b completes one full revolution every 6.917 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 602 K (+329°C / +624°F) and receiving 21.92 S⊕ (~29,834 W/m²), TOI-5777 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5777 is classified as a stellar host with an effective photospheric temperature of 4,408 K, a radius of 0.6719 R☉, a mass of 0.658 M☉, an estimated bolometric luminosity of 0.153 L☉. From Earth, TOI-5777 shines at apparent V-band magnitude 13.012 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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-5777 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,408 K |
| Stellar Radius | 0.6719 R☉ |
| Stellar Mass | 0.6580 M☉ |
| Bolometric Luminosity | 0.153 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 13.012 · G: 12.654 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 6.917 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 84.3076° |
| Mean Bulk Density | 1.82 g/cm³ (19.9 km/s vesc) |
| Insolation Flux | 21.9209 S⊕ (~29,834 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 372.700 LY (114.277 pc) |