Astronomers are always peeking through the lenses of their fancy space telescopes to learn more about the universe around us. One thing that captivates their interest the most is the bevy of distant exoplanets out there, especially those of the ‘super-Earth’ variety, which can be up to ten times more massive than Earth (hence the name).
While it seems logical that super-Earth exoplanets form via protoplanetary disks encircling young stars, the circumstances surrounding their formation remains a mystery. It’s entirely possible that the distance from the star governs the world’s chemical makeup, but this is challenging to confirm because super-Earth exoplanets are so distant and difficult to observe.
Image Credit: Thibaut Roger
In a peculiar set of circumstances, a team of European researchers happened upon a fascinating super-Earth-like exoplanet 21 light-years away dubbed HD219134 b, and it may provide some much-needed insight. The researchers describe their findings this month in the journal Monthly Notices of the Royal Astronomical Society.
There’s certainly no shortage of super-Earth-like exoplanets out there, but HD219134 b was particularly striking because of its extraordinary characteristics. HD219134 b is around 10-20 percent less dense than other exoplanets in its class, and this could be because of its unique chemical makeup.
While many super-Earth-like exoplanets are thought to be rich in iron, HD219134 b exhibits higher concentrations of certain gemstone-forming elements like aluminum and calcium instead. This, paired with the high temperatures from orbiting its host star so closely, means that HD219134 b could be chock-full of rubies and sapphires.
"Perhaps it shimmers red to blue like rubies and sapphires because these gemstones are aluminum oxides, which are common on the exoplanet," explained Caroline Dorn, an astrophysicist from the University of Zurich.
At least two other known exoplanets exhibit similar circumstances, including 55 Cancri e and WASP-47 e. Admittedly, the situation on HD219134 b is just slightly more complicated, but the conditions are similar enough that the researchers have proposed an entirely new class of Earth-like exoplanets to be recognized by astronomers going forward.
"What's exciting is that these objects are completely different from the majority of Earth-like planets," Dorn added.
As it would seem, we still have much to learn about the universe and how distant exoplanets form around their host stars, but this is a mystery that astronomers strive to solve. Perhaps more powerful space telescopes launching in the future will provide the detailed observations we need to validate these findings, but until then, all we can do is speculate.