gam Lib b
gam Lib b is a cold gas giant orbiting the K0 III star gam Lib in the constellation Libra. It lies about 155 light-years from Earth and was discovered in 2018 using the radial velocity method.
Is gam Lib b in the Habitable Zone?
gam Lib b orbits inside the inner edge of the habitable zone of gam Lib. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of gam Lib: 6.998–17.004 AU (conservative: 8.864–16.121 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 gam Lib b — one full orbit around gam Lib — lasts 414.9 Earth days, longer than an Earth year. It orbits at an average distance of 1.319 AU. Its orbit is mildly elliptical (eccentricity 0.16).
How Was gam Lib b Discovered?
gam Lib b was discovered in 2018 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 gam Lib b?
gam Lib b is 154.6 light-years (47.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1872. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,720,960 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. gam Lib b scores 0.09, ranking #4,536 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: gam Lib
gam Lib
- Spectral type
- K0 III
- Surface temperature
- 4,879 K (Sun: 5,772 K)
- Mass
- 1.78 M☉
- Radius
- 12.38 R☉
- Luminosity
- 78.9405 L☉
The gam Lib Planetary System
gam Lib b is one of 2 known planets in the gam Lib system. Its siblings:
- gam Lib c (Cold Gas Giant)
gam Lib b — Complete Data
| Mass (best estimate) | 357.87 Earth masses |
|---|---|
| Orbital period | 414.88 days |
| Orbital distance | 1.319 AU |
| Eccentricity | 0.160 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 154.6 light-years (47.4 parsecs) |
| Constellation | Libra |
| Discovery method | Radial Velocity |
| Discovery facility | Okayama Astrophysical Observatory |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2023-09-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About gam Lib b
Is gam Lib b habitable?
No — gam Lib b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is gam Lib b?
gam Lib b is about 155 light-years from Earth in the constellation Libra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,720,960 years to get there.
How long is a year on gam Lib b?
One orbit around gam Lib takes 414.9 Earth days.
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