SWEEPS-4 b
Astrophysical Synthesis & Habitability Characterization
SWEEPS-4 b is a confirmed gas giant exoplanet orbiting the star SWEEPS-4, located approximately 27723.3 light-years (8500 parsecs) from the Solar System. First announced in 2006 by Hubble Space Telescope using the Transit detection technique (producing an estimated primary transit depth of 0.4976% across the stellar disk), this world measures 9.079 Earth radii (0.81 Jupiter radii) and has a measured mass of 1207.7 Earth masses (3.8 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.9 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 14.65 g⊕ (143.67 m/s²), and an escape velocity of 129 km/s.
In its orbital architecture around SWEEPS-4, SWEEPS-4 b completes one full revolution every 4.2 Earth days at a semi-major axis of 0.055 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 142.5 km/s (compared to Earth's 29.8 km/s).
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 9.079 R⊕, SWEEPS-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 SWEEPS-4 is classified as a stellar host with a radius of 1.18 R☉, a mass of 1.24 M☉. From Earth, SWEEPS-4 shines at apparent V-band magnitude 18.8 (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: Hubble Space Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | SWEEPS-4 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | — |
| Stellar Radius | 1.1800 R☉ |
| Stellar Mass | 1.2400 M☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 18.800 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.055000 AU |
| Orbital Period | 4.2 days |
| Mean Orbital Velocity | 142.5 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 8.9 g/cm³ (129 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 27723.300 LY (8500.000 pc) |