ups Leo b
ups Leo b is a cold gas giant orbiting the G9 III star ups Leo in the constellation Leo. It lies about 172 light-years from Earth and was discovered in 2021 using the radial velocity method.
Is ups Leo b in the Habitable Zone?
ups Leo b orbits inside the inner edge of the habitable zone of ups Leo. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of ups Leo: 6.269–15.259 AU (conservative: 7.940–14.467 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on ups Leo b — one full orbit around ups Leo — lasts 385.2 Earth days, longer than an Earth year. It orbits at an average distance of 1.180 AU. Its orbit is highly elliptical (eccentricity 0.32), swinging dramatically closer to and farther from its star.
How Was ups Leo b Discovered?
ups Leo b was discovered in 2021 using the radial velocity method, with observations from Okayama Astrophysical Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is ups Leo b?
ups Leo b is 171.5 light-years (52.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1855. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,018,400 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. ups Leo b scores 0.09, ranking #4,569 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: ups Leo
ups Leo
- Spectral type
- G9 III
- Surface temperature
- 4,836 K (Sun: 5,772 K)
- Mass
- 1.48 M☉
- Radius
- 11.22 R☉
- Luminosity
- 63.1001 L☉
Planetary System
ups Leo b is the only planet known to orbit ups Leo so far.
ups Leo b — Complete Data
| Mass (best estimate) | 162.09 Earth masses |
|---|---|
| Orbital period | 385.20 days |
| Orbital distance | 1.180 AU |
| Eccentricity | 0.320 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 171.5 light-years (52.6 parsecs) |
| Constellation | Leo |
| Discovery method | Radial Velocity |
| Discovery facility | Okayama Astrophysical Observatory |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2022-01-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About ups Leo b
Is ups Leo b habitable?
No — ups Leo b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is ups Leo b?
ups Leo b is about 172 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,018,400 years to get there.
How long is a year on ups Leo b?
One orbit around ups Leo takes 385.2 Earth days.
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