WTS-2 b
WTS-2 b is a hot Jupiter orbiting the K2 V star WTS-2 in the constellation Cygnus. It lies about 3,362 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is WTS-2 b?
WTS-2 b has a radius of 15.28 times that of Earth, or 1.36 times the radius of Jupiter. Its mass is 356 times that of Earth, giving it a density of 0.54 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is WTS-2 b in the Habitable Zone?
WTS-2 b orbits inside the inner edge of the habitable zone of WTS-2. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of WTS-2: 0.441–1.066 AU (conservative: 0.559–1.011 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on WTS-2 b
The equilibrium temperature of WTS-2 b is about 2,000 K (1,727 °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 WTS-2 b — one full orbit around WTS-2 — lasts just 24.4 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.019 AU — closer to its star than Mercury is to the Sun.
How Was WTS-2 b Discovered?
WTS-2 b was discovered in 2014 using the transit method, with observations from United Kingdom Infrared Telescope.
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 WTS-2 b?
WTS-2 b is 3,361.9 light-years (1,030.8 parsecs) from Earth. Light arriving here tonight left the planet about 3,362 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 59,169,440 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. WTS-2 b scores 0.06, ranking #5,140 of 5,565 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WTS-2
WTS-2
- Spectral type
- K2 V
- Surface temperature
- 5,000 K (Sun: 5,772 K)
- Mass
- 0.82 M☉
- Radius
- 0.75 R☉
- Age
- 0.6 billion years (Sun: 4.6)
Planetary System
WTS-2 b is the only planet known to orbit WTS-2 so far.
WTS-2 b — Complete Data
| Radius | 15.278 Earth radii (1.363 Jupiter radii) |
|---|---|
| Mass | 355.97 Earth masses (1.120 Jupiter masses) |
| Density | 0.54 g/cm³ (Earth: 5.51) |
| Orbital period | 1.02 days |
| Orbital distance | 0.019 AU |
| Equilibrium temperature | 2,000 K (1,727 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 3,361.9 light-years (1,030.8 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | United Kingdom Infrared Telescope |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2015-04-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WTS-2 b
Is WTS-2 b habitable?
No — WTS-2 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is WTS-2 b?
WTS-2 b is about 3,362 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 59,169,440 years to get there.
How big is WTS-2 b compared to Earth?
WTS-2 b has 15.28 times the radius of Earth and about 356 times its mass.
How long is a year on WTS-2 b?
One orbit around WTS-2 takes 1.0 Earth days — short enough that 359 of its years would fit into one Earth year.
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