TOI-929 b
Astrophysical Synthesis & Habitability Characterization
TOI-929 b is a confirmed sub-neptune exoplanet orbiting the star TOI-929, located approximately 373.2 light-years (114.42 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 0.1182% across the stellar disk), this world measures 2.69 Earth radii and has a measured mass of 7.7 Earth masses. Combining its mass and radius yields a mean bulk density of 2.18 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 18.9 km/s.
In its orbital architecture around TOI-929, TOI-929 b completes one full revolution every 5.83 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 774 K (+501°C / +934°F) and receiving 59.73 S⊕ (~81,287 W/m²), TOI-929 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-929 is classified as a stellar host with an effective photospheric temperature of 4,457 K, a radius of 0.7174 R☉, a mass of 0.7 M☉, an estimated bolometric luminosity of 0.182 L☉. From Earth, TOI-929 shines at apparent V-band magnitude 12.489 (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-929 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,457 K |
| Stellar Radius | 0.7174 R☉ |
| Stellar Mass | 0.7000 M☉ |
| Bolometric Luminosity | 0.182 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 12.489 · G: 12.139 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 5.83 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.1958° |
| Mean Bulk Density | 2.18 g/cm³ (18.9 km/s vesc) |
| Insolation Flux | 59.7261 S⊕ (~81,287 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 373.200 LY (114.421 pc) |