Hubble Space Telescope Discovers Pitch Black Exoplanet That Hardly Reflects Any Light

The Hubble Space Telescope has made an interesting, yet gloomy-looking finding about one of the many known exoplanets in our universe. According to researchers, the sun-like star called WASP-12b is a “pitch black” exoplanet, due to the fact it barely reflects any light.

With the help of Hubble’s Space Telescope Imaging Spectrograph (STIS) instrument, researchers from McGill University in Canada and the University of Exeter in the United Kingdom teamed up to make some surprising findings about the exoplanet WASP-12b. According to the official Hubble Space Telescope website, the star’s albedo, or the amount of light it reflects, is extremely low at only 0.064 “at most,” making this pitch black exoplanet “darker than fresh asphalt,” and two times less reflective than the moon, whose albedo is rated at 0.12.

According to a report from Seeker, WASP-12b has long been familiar to astronomers, having first been discovered in 2008. The planet is often referred to as a “hot Jupiter” due to its immense size and proximity to its host star, and also has a peculiar egg-like shape and a very high daytime temperature of 4,600 degrees Fahrenheit due to that star’s gravitational pull. It’s that extreme heat that causes the exoplanet to emit a reddish hue, not unlike glowing metal.

WASP-12b is a tidally locked planet with a fixed daytime and nighttime side. And while nighttime sides are generally expected to be cooler, the Daily Mail noted that the exoplanet’s night side is a good 2,000 degrees Fahrenheit cooler, allowing water vapor and clouds to form on that part of the planet.

Furthermore, the host star constantly tears away at WASP-12b’s atmosphere, meaning that the pitch black exoplanet is also being “eaten alive,” apart from hardly reflecting any light.

Lead author Taylor Bell, a master’s astronomy student at McGill University, said in a statement that WASP-12b’s unusually high temperature may be the reason why it is a pitch black exoplanet with a very low albedo.

“There are other hot Jupiters that have been found to be remarkably black, but they are much cooler than WASP-12b. 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.”

Looking into the deeper specifics of why WASP-12b has a low albedo, Bell and his fellow researchers discovered that the exoplanet counts helium and atomic hydrogen as its key atmospheric features. As its daylight side is very hot, it is impossible for clouds to form, and alkali metals are also ionized as they gain or lose electrons. Hydrogen molecules are broken up and transformed into atomic hydrogen due to this extreme heat, giving the exoplanet an atmosphere more akin to that of a low-mass star.

Although it’s noteworthy that WASP-12b is now being referred to as a “pitch black” exoplanet, there’s a chance that the planet might not be long for this universe. The American Astronomical Society wrote in July that WASP-12b’s orbit is “changing over time” and possibly “decaying,” which could mean its already-short orbital period of 1.09 days will shrink to zero about 3.2 million years from now. In other words, the exoplanet might already been in the final 0.2 percent of its lifetime.

[Featured Image by d1sk/iStock]