XO-2 N b
XO-2 N b is a hot Jupiter orbiting the G8 V star XO-2 N in the constellation Lynx. It lies about 503 light-years from Earth and was discovered in 2007 using the transit method.
Is XO-2 N b in the Habitable Zone?
XO-2 N b orbits inside the inner edge of the habitable zone of XO-2 N. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of XO-2 N: 0.646–1.544 AU (conservative: 0.818–1.464 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 XO-2 N b — one full orbit around XO-2 N — lasts 2.62 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.037 AU — closer to its star than Mercury is to the Sun.
How Was XO-2 N b Discovered?
XO-2 N b was discovered in 2007 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-2 N b?
XO-2 N b is 503.2 light-years (154.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1523. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 8,856,320 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-2 N b scores 0.08, ranking #4,653 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: XO-2 N
XO-2 N b belongs to a system of 2 stars; it orbits XO-2 N.
XO-2 N
- Spectral type
- G8 V
- Surface temperature
- 5,290 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 1.00 R☉
Planetary System
XO-2 N b is the only planet known to orbit XO-2 N so far.
XO-2 N b — Complete Data
| Mass (best estimate) | 188.79 Earth masses |
|---|---|
| Orbital period | 2.62 days |
| Orbital distance | 0.037 AU |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 503.2 light-years (154.3 parsecs) |
| Constellation | Lynx |
| Discovery method | Transit |
| Discovery facility | XO |
| Discovery year | 2007 |
Data: NASA Exoplanet Archive, last updated 2026-05-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About XO-2 N b
Is XO-2 N b habitable?
No — XO-2 N b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is XO-2 N b?
XO-2 N b is about 503 light-years from Earth in the constellation Lynx. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 8,856,320 years to get there.
How long is a year on XO-2 N b?
One orbit around XO-2 N takes 2.6 Earth days — short enough that 140 of its years would fit into one Earth year.
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