AT2021ueyL b
Astrophysical Synthesis & Habitability Characterization
AT2021ueyL b is a confirmed gas giant exoplanet orbiting the star AT2021ueyL, located approximately 3392 light-years (1040 parsecs) from the Solar System. First announced in 2025 by Multiple Observatories using the Microlensing detection technique (detected via relativistic gravitational lensing of a background source star), this world measures 13.6 Earth radii (1.21 Jupiter radii) and has a measured mass of 425.89 Earth masses (1.34 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.93 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.3 g⊕ (22.56 m/s²), and an escape velocity of 62.6 km/s.
In its orbital architecture around AT2021ueyL, AT2021ueyL b completes one full revolution every 4168.69 Earth days (11.41Julian years) at a semi-major axis of 4.01 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 10.5 km/s (compared to Earth's 29.8 km/s).
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.600 R⊕, AT2021ueyL 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 AT2021ueyL is classified as a low-mass red dwarf of spectral type M V with an effective photospheric temperature of 3,680 K, a mass of 0.49 M☉.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | AT2021ueyL |
| Spectral Type | M V |
| Effective Temp (Teff) | 3,680 K |
| Stellar Radius | — |
| Stellar Mass | 0.4900 M☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | — |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 4.010000 AU |
| Orbital Period | 4168.69 days |
| Mean Orbital Velocity | 10.5 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.93 g/cm³ (62.6 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3392.000 LY (1040.000 pc) |