KOI-1783.02
Astrophysical Synthesis & Habitability Characterization
KOI-1783.02 is a confirmed sub-neptune exoplanet orbiting the star KOI-1783, located approximately 2823.6 light-years (865.73 parsecs) from the Solar System. First announced in 2020 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1904% across the stellar disk), this world measures 5.44 Earth radii (0.49 Jupiter radii) and has a measured mass of 15 Earth masses. Combining its mass and radius yields a mean bulk density of 0.51 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.51 g⊕ (5 m/s²), and an escape velocity of 18.6 km/s.
In its orbital architecture around KOI-1783, KOI-1783.02 completes one full revolution every 284.215 Earth days at a semi-major axis of 0.86695 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 33.2 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.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 5.440 R⊕, KOI-1783.02 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 KOI-1783 is classified as a stellar host with an effective photospheric temperature of 5,922 K, a radius of 1.143 R☉, a mass of 1.076 M☉, an estimated bolometric luminosity of 1.442 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.2 Gyr and a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, KOI-1783 shines at apparent V-band magnitude 13.978 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KOI-1783 system is a multi-planet architecture hosting 2 confirmed worlds, with KOI-1783.02 sharing its stellar neighborhood alongside KOI-1783.01.
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: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | KOI-1783 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,922 K |
| Stellar Radius | 1.1430 R☉ |
| Stellar Mass | 1.0760 M☉ |
| Bolometric Luminosity | 1.442 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | 0.200 Gyr |
| Apparent Magnitude | V: 13.978 · G: 13.906 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.866950 AU |
| Orbital Period | 284.215 days |
| Mean Orbital Velocity | 33.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6500° |
| Mean Bulk Density | 0.51 g/cm³ (18.6 km/s vesc) |
| Insolation Flux | 2.4900 S⊕ (~3,389 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2823.600 LY (865.730 pc) |