The planet, 55 Cancri e, had previously been identified and its mass
estimated at around eight times that of Earth. But it was first directly
observed last year, giving researchers the chance to measure its
radius, which came out around twice that of Earth.
Star composition is much easier to pin down from afar and the team
had already established it was extremely high in carbon and low in
oxygen, suggesting that the surrounding planets would probably be short
of water ice and certain other components.
"Stars are simple — given a star's mass and age, you know its basic
structure and history," David Spergel, professor of astronomy and chair
of astrophysical sciences at Princeton University, explained to Yale
News. "Planets Diamond planet are much more complex."
The researchers were already aware that 55 Cancri e was very unlike
Earth, with an orbit of only 18 hours around the sun. Surface
temperatures are estimated to run as high as 3,900 degrees Fahrenheit.
Still, with the latest bits of information, the Yale team were able
to put together a projection of the planet's composition - mostly
carbon, iron, silicon carbide and some silicates.
"This is our first glimpse of a rocky world with a fundamentally
different chemistry from Earth," said Nikku Madhusudhan, a Yale
postdoctoral researcher and the lead researcher on the project. "The
surface of this planet is likely covered in graphite and diamond rather
than water and granite."
As much as one-third of the planet's total mass is estimated to be
diamond. That amounts to nearly three times Earth's mass, just in
diamond.
As much as a glittering gem in the night sky might seem fascinating,
the research leads to the bigger revelation that some of the more exotic
planet types imagined by scientists could realistically exist.
"This ‘diamond-rich super-Earth’ is likely just one example of the
rich sets of discoveries that await us as we begin to explore planets
around nearby stars," Spergel suggested.
