A planet orbiting a star 1,400 light-years from Earth is darker than asphalt.
New data from the Hubble Space Telescope shows that WASP-12b, which has a radius twice as large as Jupiter’s, is an incredibly hot planet with a very low albedo—meaning that it’s incredibly dark.
WASP-12b is known as a “hot Jupiter” because it’s about the size of our solar system’s largest planet, yet orbits very close to its star. That close distance is also probably responsible for the alien world’s pitch-black color.
“For those planets, it is suggested that things like clouds and alkali metals are the reason for the absorption of light, but those don’t work for WASP-12b because it is so incredibly hot.”
WASP-12b is so close to its star that clouds can’t form on its day side, and the planet is actually gravitationally stretched into an oval shape.
Hubble observed WASP-12b when the planet’s star passed in front of the planet from Earth’s perspective in October 2016.
This allowed scientists to see exactly how much light the world reflected, giving them a sense of what its atmosphere is made of.
According to the study, WASP-12b’s atmosphere seems to be made of atomic hydrogen and helium.
“The fact that the first two exoplanets with measured spectral albedo exhibit significant differences demonstrates the importance of these types of spectral observations and highlights the great diversity among hot Jupiters,” Bell said.