TOI-1736 b
Astrophysical Synthesis & Habitability Characterization
TOI-1736 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1736, located approximately 290.1 light-years (88.95 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0417% across the stellar disk), this world measures 3.182 Earth radii (0.28 Jupiter radii) and has a measured mass of 12.3 Earth masses. Combining its mass and radius yields a mean bulk density of 2.11 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.21 g⊕ (11.87 m/s²), and an escape velocity of 22 km/s.
In its orbital architecture around TOI-1736, TOI-1736 b completes one full revolution every 7.073 Earth days at a semi-major axis of 0.073 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 112.3 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 1100 K (+827°C / +1521°F) and receiving 329.60 S⊕ (~448,586 W/m²), TOI-1736 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1736 is classified as a stellar host with an effective photospheric temperature of 5,636 K, a radius of 1.4286 R☉, a mass of 1.0373 M☉, an estimated bolometric luminosity of 1.848 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.2 Gyr and a metallicity of [Fe/H] = 0.148 dex (metal-rich relative to the Sun). From Earth, TOI-1736 shines at apparent V-band magnitude 8.953 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The TOI-1736 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-1736 b sharing its stellar neighborhood alongside TOI-1736 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-1736 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,636 K |
| Stellar Radius | 1.4286 R☉ |
| Stellar Mass | 1.0373 M☉ |
| Bolometric Luminosity | 1.848 L☉ |
| Metallicity [Fe/H] | 0.148 dex |
| Stellar Age | 9.200 Gyr |
| Apparent Magnitude | V: 8.953 · G: 8.780 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.073000 AU |
| Orbital Period | 7.073 days |
| Mean Orbital Velocity | 112.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 87.3000° |
| Mean Bulk Density | 2.11 g/cm³ (22 km/s vesc) |
| Insolation Flux | 329.6000 S⊕ (~448,586 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 290.100 LY (88.948 pc) |