TOI-1233.01
Astrophysical Synthesis & Habitability Characterization
TOI-1233.01 is a confirmed sub-neptune exoplanet orbiting the star HD 108236, located approximately 210.7 light-years (64.6 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0704% across the stellar disk), this world measures 2.539 Earth radii and has a measured mass of 6.98 Earth masses. Combining its mass and radius yields a mean bulk density of 2.35 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.5 km/s.
In its orbital architecture around HD 108236, TOI-1233.01 completes one full revolution every 14.176 Earth days at a semi-major axis of 0.1074 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.055 carries the world between 0.1015 AU at periapsis and 0.1133 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 708 K (+435°C / +815°F) and receiving 53.88 S⊕ (~73,330 W/m²), TOI-1233.01 orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 108236 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,660 K, a radius of 0.877 R☉, a mass of 0.869 M☉, an estimated bolometric luminosity of 0.708 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.7 Gyr and a metallicity of [Fe/H] = -0.28 dex (metal-poor relative to the Sun). From Earth, HD 108236 shines at apparent V-band magnitude 9.25 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 108236 system is a multi-planet architecture hosting 5 confirmed worlds, with TOI-1233.01 sharing its stellar neighborhood alongside HD 108236 b, HD 108236 c, HD 108236 e, HD 108236 f.
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 108236 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,660 K |
| Stellar Radius | 0.8770 R☉ |
| Stellar Mass | 0.8690 M☉ |
| Bolometric Luminosity | 0.708 L☉ |
| Metallicity [Fe/H] | -0.280 dex |
| Stellar Age | 6.700 Gyr |
| Apparent Magnitude | V: 9.250 · G: 9.087 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.107400 AU |
| Orbital Period | 14.176 days |
| Mean Orbital Velocity | 82.4 km/s |
| Orbital Eccentricity (e) | 0.05500 |
| Orbital Inclination (i) | 89.0600° |
| Mean Bulk Density | 2.35 g/cm³ (18.5 km/s vesc) |
| Insolation Flux | 53.8795 S⊕ (~73,330 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 210.700 LY (64.598 pc) |