AT2021ueyL b
AT2021ueyL b is a cold gas giant orbiting the M V star AT2021ueyL in the constellation Pegasus. It lies about 3,392 light-years from Earth and was discovered in 2025 using the microlensing method.
Is AT2021ueyL b in the Habitable Zone?
The position of AT2021ueyL b relative to the habitable zone of AT2021ueyL cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on AT2021ueyL b — one full orbit around AT2021ueyL — lasts 4,168.7 Earth days, longer than an Earth year. It orbits at an average distance of 4.010 AU.
How Was AT2021ueyL b Discovered?
AT2021ueyL b was discovered in 2025 using the microlensing method, with observations from Multiple Observatories.
Gravitational microlensing detects a planet when its host star passes in front of a more distant background star, and the planet's gravity adds a brief, telltale spike to the magnified starlight. It can find planets thousands of light-years away.
How Far Away Is AT2021ueyL b?
AT2021ueyL b is 3,392.0 light-years (1,040.0 parsecs) from Earth. Light arriving here tonight left the planet about 3,392 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 59,699,200 years to make the journey.
The Host Star: AT2021ueyL
AT2021ueyL
- Spectral type
- M V
- Surface temperature
- 3,680 K (Sun: 5,772 K)
- Mass
- 0.49 M☉
Planetary System
AT2021ueyL b is the only planet known to orbit AT2021ueyL so far.
AT2021ueyL b — Complete Data
| Mass | 425.89 Earth masses (1.340 Jupiter masses) |
|---|---|
| Orbital period | 4,168.69 days |
| Orbital distance | 4.010 AU |
| Distance from Earth | 3,392.0 light-years (1,040.0 parsecs) |
| Constellation | Pegasus |
| Discovery method | Microlensing |
| Discovery facility | Multiple Observatories |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-05-07. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About AT2021ueyL b
Is AT2021ueyL b habitable?
AT2021ueyL b is not known to orbit within the habitable zone of AT2021ueyL, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is AT2021ueyL b?
AT2021ueyL b is about 3,392 light-years from Earth in the constellation Pegasus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 59,699,200 years to get there.
How long is a year on AT2021ueyL b?
One orbit around AT2021ueyL takes 4,168.7 Earth days.
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