Kepler-1739 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1739 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1739, located approximately 2556 light-years (783.67 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0855% across the stellar disk), this world measures 2.431 Earth radii and has a measured mass of 6.48 Earth masses. Combining its mass and radius yields a mean bulk density of 2.49 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.1 g⊕ (10.79 m/s²), and an escape velocity of 18.3 km/s.
In its orbital architecture around Kepler-1739, Kepler-1739 b completes one full revolution every 7.344 Earth days at a semi-major axis of 0.0697 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 103.3 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 839 K (+566°C / +1051°F) and receiving 117.50 S⊕ (~159,918 W/m²), Kepler-1739 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1739 is classified as a stellar host with an effective photospheric temperature of 5,757 K, a radius of 0.762 R☉, a mass of 0.865 M☉, an estimated bolometric luminosity of 0.572 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.4 Gyr and a metallicity of [Fe/H] = -0.5 dex (metal-poor relative to the Sun). From Earth, Kepler-1739 shines at apparent V-band magnitude 14.899 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
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 | Kepler-1739 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,757 K |
| Stellar Radius | 0.7620 R☉ |
| Stellar Mass | 0.8650 M☉ |
| Bolometric Luminosity | 0.572 L☉ |
| Metallicity [Fe/H] | -0.500 dex |
| Stellar Age | 0.400 Gyr |
| Apparent Magnitude | V: 14.899 · G: 14.642 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.069700 AU |
| Orbital Period | 7.344 days |
| Mean Orbital Velocity | 103.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7800° |
| Mean Bulk Density | 2.49 g/cm³ (18.3 km/s vesc) |
| Insolation Flux | 117.5000 S⊕ (~159,918 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2556.000 LY (783.666 pc) |