Astronomers recently discovered an exoplanet they’ve been studying since 2008 is pitch black, reflecting almost no light. The new findings could change what the researchers previously hypothesized about WASP-12b’s atmosphere. Taylor Bell, a master’s student at McGill University, described the exoplanet as darker than fresh asphalt.
There’s a pitch black planet out there in space. An international group of astronomers utilized the Space Telescope Imaging Spectograph on the NASA/ESA Hubble Space Telescope to measure the albedo – or how much light a planet reflects – of WASP-12b. The exoplanet’s albedo is incredibly low, which reportedly surprised the researchers. WASP-12b is two times less reflective than Earth’s Moon.
Why should we care about an exoplanet’s albedo? It can tell us about the planet’s atmosphere: scientists now think WASP-12b’s atmosphere is comprised of helium and atomic hydrogen. Bell said in a statement, “The low albedo shows we still have a lot to learn about WASP-12b and other similar exoplanets.”
WASP-12b is classified as a hot Jupiter, and has a radius almost double Jupiter’s. Its daylight side has a surface temperature of around 2,600 degrees Celsius – and the high temperature may offer an explanation for the low albedo.
“There are other hot Jupiters that have been found to be remarkably black, but they are much cooler than WASP-12b,” Bell said. “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.”
14 researchers were involved in the work, from institutions in Canada, the United States and the United Kingdom. The Astrophysical Journal Letters published the study earlier this month.