TOI-1836 b
Astrophysical Synthesis & Habitability Characterization
TOI-1836 b is a confirmed gas giant exoplanet orbiting the star TOI-1836, located approximately 625.1 light-years (191.65 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.2165% across the stellar disk), this world measures 8.003 Earth radii (0.71 Jupiter radii) and has a measured mass of 38.457 Earth masses (0.12 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.41 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.6 g⊕ (5.88 m/s²), and an escape velocity of 24.5 km/s.
In its orbital architecture around TOI-1836, TOI-1836 b completes one full revolution every 20.381 Earth days at a semi-major axis of 0.1597 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 85.2 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 966 K (+693°C / +1279°F) and receiving 153.52 S⊕ (~208,939 W/m²), TOI-1836 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1836 is classified as a stellar host with an effective photospheric temperature of 6,380 K, a radius of 1.577 R☉, a mass of 1.307 M☉, an estimated bolometric luminosity of 3.697 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.6 Gyr and a metallicity of [Fe/H] = -0.101 dex (metal-poor relative to the Sun). From Earth, TOI-1836 shines at apparent V-band magnitude 9.765 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The TOI-1836 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-1836 b sharing its stellar neighborhood alongside TOI-1836 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 | TOI-1836 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,380 K |
| Stellar Radius | 1.5770 R☉ |
| Stellar Mass | 1.3070 M☉ |
| Bolometric Luminosity | 3.697 L☉ |
| Metallicity [Fe/H] | -0.101 dex |
| Stellar Age | 6.600 Gyr |
| Apparent Magnitude | V: 9.765 · G: 9.645 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.159700 AU |
| Orbital Period | 20.381 days |
| Mean Orbital Velocity | 85.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.7400° |
| Mean Bulk Density | 0.41 g/cm³ (24.5 km/s vesc) |
| Insolation Flux | 153.5185 S⊕ (~208,939 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 625.100 LY (191.649 pc) |