KOINTREAU-4 b
Astrophysical Synthesis & Habitability Characterization
KOINTREAU-4 b is a confirmed gas giant exoplanet orbiting the star 2MASS J16262785-2625152, located approximately 474.3 light-years (145.43 parsecs) from the Solar System. First announced in 2026 by W. M. Keck Observatory using the Imaging detection technique (resolved directly via high-contrast coronagraphic or interferometric imaging), this world measures 12.2 Earth radii (1.09 Jupiter radii) and has a measured mass of 4862.775 Earth masses (15.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 14.77 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 32.67 g⊕ (320.38 m/s²), and an escape velocity of 223.3 km/s.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 12.200 R⊕, KOINTREAU-4 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 2MASS J16262785-2625152 is classified as a low-mass red dwarf of spectral type M4.5 with an effective photospheric temperature of 3,252 K. Stellar evolution modeling indicates an estimated stellar age of 0.011 Gyr. From Earth, 2MASS J16262785-2625152 shines at apparent V-band magnitude 15.902 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | 2MASS J16262785-2625152 |
| Spectral Type | M4.5 |
| Effective Temp (Teff) | 3,252 K |
| Stellar Radius | — |
| Stellar Mass | — |
| Metallicity [Fe/H] | — |
| Stellar Age | 0.011 Gyr |
| Apparent Magnitude | V: 15.902 · G: 14.102 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 182.000000 AU |
| Orbital Period | — |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 14.77 g/cm³ (223.3 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 474.300 LY (145.434 pc) |