Kepler-1550 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1550 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1550, located approximately 3845.4 light-years (1179.01 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0622% across the stellar disk), this world measures 3.02 Earth radii (0.27 Jupiter radii) and has a measured mass of 9.38 Earth masses. Combining its mass and radius yields a mean bulk density of 1.88 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.03 g⊕ (10.1 m/s²), and an escape velocity of 19.7 km/s.
In its orbital architecture around Kepler-1550, Kepler-1550 b completes one full revolution every 225.583 Earth days at a semi-major axis of 0.7681 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 37 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 3.020 R⊕, Kepler-1550 b 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 Kepler-1550 is classified as a stellar host with an effective photospheric temperature of 5,991 K, a radius of 1.11 R☉, a mass of 1.07 M☉, an estimated bolometric luminosity of 1.424 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.55 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-1550 shines at apparent V-band magnitude 15.107 (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-1550 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,991 K |
| Stellar Radius | 1.1100 R☉ |
| Stellar Mass | 1.0700 M☉ |
| Bolometric Luminosity | 1.424 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 3.550 Gyr |
| Apparent Magnitude | V: 15.107 · G: 14.884 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.768100 AU |
| Orbital Period | 225.583 days |
| Mean Orbital Velocity | 37 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9800° |
| Mean Bulk Density | 1.88 g/cm³ (19.7 km/s vesc) |
| Insolation Flux | 2.3050 S⊕ (~3,137 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3845.400 LY (1179.010 pc) |