HD 109833 b
Astrophysical Synthesis & Habitability Characterization
HD 109833 b is a confirmed sub-neptune exoplanet orbiting the star HD 109833, located approximately 259.5 light-years (79.56 parsecs) from the Solar System. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0701% across the stellar disk), this world measures 2.888 Earth radii and has a measured mass of 8.69 Earth masses. Combining its mass and radius yields a mean bulk density of 1.99 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 HD 109833, HD 109833 b completes one full revolution every 9.189 Earth days. Its moderate orbital eccentricity of e = 0.18 driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 786 K (+513°C / +955°F) and receiving 63.46 S⊕ (~86,368 W/m²), HD 109833 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 109833 is classified as a stellar host with an effective photospheric temperature of 5,881 K, a radius of 1 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 1.073 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.027 Gyr and a metallicity of [Fe/H] = -0.07 dex (near-solar heavy-element abundance). From Earth, HD 109833 shines at apparent V-band magnitude 9.29 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 109833 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 109833 b sharing its stellar neighborhood alongside HD 109833 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 | HD 109833 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,881 K |
| Stellar Radius | 1.0000 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 1.073 L☉ |
| Metallicity [Fe/H] | -0.070 dex |
| Stellar Age | 0.027 Gyr |
| Apparent Magnitude | V: 9.290 · G: 9.137 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 9.189 days |
| Orbital Eccentricity (e) | 0.18000 |
| Orbital Inclination (i) | 88.1300° |
| Mean Bulk Density | 1.99 g/cm³ (19.4 km/s vesc) |
| Insolation Flux | 63.4589 S⊕ (~86,368 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 259.500 LY (79.556 pc) |