A Planet Made of Diamonds

Beyond our solar system lies an extraordinary exoplanet known as 55 Cancri e, or Janssen, a "super-Earth" that has captivated astronomers since its discovery in 2004. This world, found orbiting a star in the constellation Cancer, is remarkable not only for being roughly twice the size of Earth and possessing a mass about eight times greater, but also for its incredibly tight orbit. Completing a full rotation around its host star in less than 18 hours, 55 Cancri e experiences extreme conditions, with surface temperatures hot enough to melt rock. It was initially discovered through the radial velocity method, detecting subtle wobbles in its star, and later confirmed by observing its transit across the stellar disk in 2011.

The intriguing hypothesis that much of 55 Cancri e could be composed of diamond emerged from scientific models in 2012. This theory was based on observations of its parent star, 55 Cancri A, which was found to have a significantly higher carbon-to-oxygen ratio compared to our Sun. Given the abundance of carbon in the system and the immense pressures and scorching temperatures within such a massive, dense planet, scientists theorized that carbon within 55 Cancri e's interior would crystalize into diamond, alongside graphite.

While subsequent research has led to ongoing discussions about the precise carbon-to-oxygen ratio of the star and, consequently, the exact internal makeup of the planet, 55 Cancri e remains a world of extreme density and peculiar composition. Modern observations, including those from the James Webb Space Telescope (Deals), indicate that its surface is likely a global ocean of molten magma, from which a substantial atmosphere rich in carbon dioxide or carbon monoxide may be bubbling. This fascinating exoplanet continues to offer a unique laboratory for understanding the diverse and often extreme possibilities of planetary formation beyond our own familiar solar system.