XO-6 b
XO-6 b is a hot Jupiter orbiting the F5 star XO-6 in the constellation Camelopardalis. It lies about 768 light-years from Earth and was discovered in 2016 using the transit method.
How Big Is XO-6 b?
XO-6 b has a radius of 23.20 times that of Earth, or 2.07 times the radius of Jupiter. Its mass is 1,398 times that of Earth, giving it a density of 0.62 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is XO-6 b in the Habitable Zone?
XO-6 b orbits inside the inner edge of the habitable zone of XO-6. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of XO-6: 1.853–4.288 AU (conservative: 2.347–4.065 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on XO-6 b
The equilibrium temperature of XO-6 b is about 1,577 K (1,304 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on XO-6 b — one full orbit around XO-6 — lasts 3.77 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.082 AU — closer to its star than Mercury is to the Sun.
How Was XO-6 b Discovered?
XO-6 b was discovered in 2016 using the transit method, with observations from XO.
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 XO-6 b?
XO-6 b is 768.0 light-years (235.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1258. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 13,516,800 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. XO-6 b scores 0.04, ranking #5,319 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: XO-6
XO-6
- Spectral type
- F5
- Surface temperature
- 6,720 K (Sun: 5,772 K)
- Mass
- 1.47 M☉
- Radius
- 1.93 R☉
- Age
- 1.9 billion years (Sun: 4.6)
Planetary System
XO-6 b is the only planet known to orbit XO-6 so far.
XO-6 b — Complete Data
| Radius | 23.203 Earth radii (2.070 Jupiter radii) |
|---|---|
| Mass | 1,398.45 Earth masses (4.400 Jupiter masses) |
| Density | 0.62 g/cm³ (Earth: 5.51) |
| Orbital period | 3.77 days |
| Orbital distance | 0.082 AU |
| Equilibrium temperature | 1,577 K (1,304 °C) |
| Earth Similarity Index | 0.04 |
| Distance from Earth | 768.0 light-years (235.5 parsecs) |
| Constellation | Camelopardalis |
| Discovery method | Transit |
| Discovery facility | XO |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-12-20. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About XO-6 b
Is XO-6 b habitable?
No — XO-6 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is XO-6 b?
XO-6 b is about 768 light-years from Earth in the constellation Camelopardalis. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 13,516,800 years to get there.
How big is XO-6 b compared to Earth?
XO-6 b has 23.20 times the radius of Earth and about 1,398 times its mass.
How long is a year on XO-6 b?
One orbit around XO-6 takes 3.8 Earth days — short enough that 97 of its years would fit into one Earth year.
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