KELT-8 b
KELT-8 b is a hot Jupiter orbiting KELT-8 in the constellation Hercules. It lies about 644 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is KELT-8 b?
KELT-8 b has a radius of 18.16 times that of Earth, or 1.62 times the radius of Jupiter. Its mass is 210 times that of Earth.
Is KELT-8 b in the Habitable Zone?
The position of KELT-8 b relative to the habitable zone of KELT-8 cannot be precisely determined from the available orbital data.
Habitable zone of KELT-8: 1.088–2.565 AU (conservative: 1.378–2.432 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 KELT-8 b — one full orbit around KELT-8 — lasts 3.24 Earth days, shorter than Mercury's 88-day year. Its orbit is nearly circular (eccentricity 0.040).
How Was KELT-8 b Discovered?
KELT-8 b was discovered in 2015 using the transit method, with observations from KELT.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is KELT-8 b?
KELT-8 b is 644.4 light-years (197.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1382. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 11,341,440 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. KELT-8 b scores 0.05, ranking #5,265 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: KELT-8
KELT-8
- Surface temperature
- 5,754 K (Sun: 5,772 K)
- Mass
- 0.81 M☉
- Radius
- 1.46 R☉
Planetary System
KELT-8 b is the only planet known to orbit KELT-8 so far.
KELT-8 b — Complete Data
| Radius | 18.159 Earth radii (1.620 Jupiter radii) |
|---|---|
| Mass | 209.77 Earth masses (0.660 Jupiter masses) |
| Orbital period | 3.24 days |
| Eccentricity | 0.040 |
| Earth Similarity Index | 0.05 |
| Distance from Earth | 644.4 light-years (197.6 parsecs) |
| Constellation | Hercules |
| Discovery method | Transit |
| Discovery facility | KELT |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2018-04-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About KELT-8 b
Is KELT-8 b habitable?
KELT-8 b is not known to orbit within the habitable zone of KELT-8, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is KELT-8 b?
KELT-8 b is about 644 light-years from Earth in the constellation Hercules. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 11,341,440 years to get there.
How big is KELT-8 b compared to Earth?
KELT-8 b has 18.16 times the radius of Earth and about 210 times its mass.
How long is a year on KELT-8 b?
One orbit around KELT-8 takes 3.2 Earth days — short enough that 113 of its years would fit into one Earth year.
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