TIC 434398831 b
Astrophysical Synthesis & Habitability Characterization
TIC 434398831 b 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 0.1253% across the stellar disk), this world measures 3.51 Earth radii (0.31 Jupiter radii) and has a measured mass of 12.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.54 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.98 g⊕ (9.61 m/s²), and an escape velocity of 20.8 km/s.
In its orbital architecture around TIC 434398831, TIC 434398831 b completes one full revolution every 3.686 Earth days at a semi-major axis of 0.04641 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 137 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.04 (ranging from 0.0446 AU at periapsis to 0.0483 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1250 K (+977°C / +1791°F) and receiving 333.63 S⊕ (~454,072 W/m²), TIC 434398831 b 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 b sharing its stellar neighborhood alongside TIC 434398831 c.
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) | 0.046410 AU |
| Orbital Period | 3.686 days |
| Mean Orbital Velocity | 137 km/s |
| Orbital Eccentricity (e) | 0.04000 |
| Orbital Inclination (i) | 88.2000° |
| Mean Bulk Density | 1.54 g/cm³ (20.8 km/s vesc) |
| Insolation Flux | 333.6313 S⊕ (~454,072 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 707.800 LY (217.011 pc) |