Diamond 'Super-Earth' May Not Be Quite as Precious as Once Thought, Study Finds

A planet once known as the galaxy's first “diamond world” may be less blingy than it seemed. Around 40 light-years from Earth, the exoplanet 55 Cancri e was suspected to be made largely of carbon, leading to headlines of a diamond planet. But a new investigation, led by Johanna Teske of the University of Arizona, calls that conclusion into question. Re-analysing telescope data, her team concluded that the host star has a lot more oxygen than originally believed, making the possibility that its planet formed with a carbon-dominant atmosphere less likely.

New Analysis Challenges 55 Cancri e's Reputation as a Diamond-Rich Exoplanet

According to a University of Arizona report, studies implied 55 Cancri e may be wrapped in a layer of diamond, yet Teske's team found oxygen is 25% too abundant to sustain the carbon-heavy scenario. Astronomers create computer models to simulate the rocky planets, such as 55 Cancri e, based on radius, mass, and density, taking into account the star's makeup. Even at high oxygen or high carbon, a pocket can form planets in spite of uncertainties.

55 Cancri e, in the constellation of Cancer, orbits in a year, has a high surface temperature, and is well away from its star.

By reassessing telescope data, scientists found its host star contains more oxygen than carbon, weakening earlier claims of a diamond-heavy interior. The findings highlight uncertainties in star-to-planet chemistry and the complexity of exoplanetary science.

The field of exoplanet studies, on the other hand, is relatively young and also has uncertain star-to-planet depletion and accretion composition. Better instruments might change theories and show hidden surprises.