TIC 434398831 c
Astrophysical Synthesis & Habitability Characterization
TIC 434398831 c is a confirmed sub-neptune exoplanet orbiting the star TIC 434398831, located approximately 707.8 light-years (217.01 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.3224% across the stellar disk), this world measures 5.63 Earth radii (0.5 Jupiter radii) and has a measured mass of 27 Earth masses. Combining its mass and radius yields a mean bulk density of 0.83 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.85 g⊕ (8.34 m/s²), and an escape velocity of 24.5 km/s.
In its orbital architecture around TIC 434398831, TIC 434398831 c completes one full revolution every 6.21 Earth days at a semi-major axis of 0.06572 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 115.1 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.013 (ranging from 0.0649 AU at periapsis to 0.0666 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1050 K (+777°C / +1431°F) and receiving 166.38 S⊕ (~226,440 W/m²), TIC 434398831 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TIC 434398831 is classified as a solar-type yellow star of spectral type G4 V with an effective photospheric temperature of 5,638 K, a radius of 0.909 R☉, a mass of 0.992 M☉, an estimated bolometric luminosity of 0.749 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.061 Gyr and a metallicity of [Fe/H] = -0.081 dex (near-solar heavy-element abundance). From Earth, TIC 434398831 shines at apparent V-band magnitude 11.682 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TIC 434398831 system is a multi-planet architecture hosting 2 confirmed worlds, with TIC 434398831 c sharing its stellar neighborhood alongside TIC 434398831 b.
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 | TIC 434398831 |
| Spectral Type | G4 V |
| Effective Temp (Teff) | 5,638 K |
| Stellar Radius | 0.9090 R☉ |
| Stellar Mass | 0.9920 M☉ |
| Bolometric Luminosity | 0.749 L☉ |
| Metallicity [Fe/H] | -0.081 dex |
| Stellar Age | 0.061 Gyr |
| Apparent Magnitude | V: 11.682 · G: 11.789 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.065720 AU |
| Orbital Period | 6.21 days |
| Mean Orbital Velocity | 115.1 km/s |
| Orbital Eccentricity (e) | 0.01300 |
| Orbital Inclination (i) | 87.7900° |
| Mean Bulk Density | 0.83 g/cm³ (24.5 km/s vesc) |
| Insolation Flux | 166.3776 S⊕ (~226,440 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 707.800 LY (217.011 pc) |