WTS-2 b
WTS-2 b is a hot Jupiter orbiting the K2 V star WTS-2 in the constellation Cygnus. It 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.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
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.
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 #5,143 of 5,568 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 |
| 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 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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