TOI-1736 c
Astrophysical Synthesis & Habitability Characterization
TOI-1736 c is a confirmed gas giant exoplanet orbiting the star TOI-1736, located approximately 290.1 light-years (88.95 parsecs) from the Solar System. First announced in 2023 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 2800 Earth masses (8.81 Jupiter masses). Combining its mass and radius yields a mean bulk density of 7.9 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 17.92 g⊕ (175.74 m/s²), and an escape velocity of 167.4 km/s.
In its orbital architecture around TOI-1736, TOI-1736 c completes one full revolution every 571.25 Earth days (1.56Julian years) at a semi-major axis of 1.37 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 26.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.3685, swinging from 0.8652 AU at periapsis out to 1.8748 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.500 R⊕, TOI-1736 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
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 c sharing its stellar neighborhood alongside TOI-1736 b.
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: Haute-Provence Observatory · 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) | 1.370000 AU |
| Orbital Period | 571.25 days |
| Mean Orbital Velocity | 26.1 km/s |
| Orbital Eccentricity (e) | 0.36850 |
| Orbital Inclination (i) | 69.0000° |
| Mean Bulk Density | 7.9 g/cm³ (167.4 km/s vesc) |
| Insolation Flux | 0.9000 S⊕ (~1,225 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 290.100 LY (88.948 pc) |