Atmosphere of the rocky exoplanet Gliese 486 b studied with infrared observations

Star system: WASP 189 | Distance from the Sun: 323 light years

Gliese 486 b is a rocky exoplanet orbiting a Red dwarf star at a distance of about 26 light-years from the Solar System. Because it orbits very close to its host star, the planet is extremely hot, with surface temperatures reaching approximately 700 Kelvin. Observations from the James Webb Space Telescope were used to examine the light from the star as the planet passed in front of it to search for an atmosphere.

The research indicates that the planet lacks a significant atmosphere, suggesting that the rocky surface is directly exposed to space. This conclusion is based on the absence of expected water vapor or carbon-based gases, which would be visible in the infrared spectrum if a thick atmosphere were present. These findings challenge previous models that suggested such planets could retain an atmosphere despite intense radiation.

By measuring the infrared light fluctuations during the planet's transit, the data revealed that the planetary emission is consistent with a bare rock surface. This suggests that the intense stellar activity of the Red dwarf host star may have stripped away any initial atmospheric gases, a common challenge for planets orbiting this type of star.

Key findings
- Gliese 486 b shows no signs of a water vapor atmosphere.
- Infrared observations are consistent with a bare rock surface.
- The planet has a surface temperature of approximately 700 Kelvin.
- Stellar radiation from the Red dwarf likely eroded any atmosphere the planet might have possessed.

Scientific study

The breaking of cold traps and onset of titanium in ultra-hot Jupiter atmospheres: WASP-189b in context (external link)