Earth and Space

The polystyrene planet

Stories from Physics for 11-14 14-16 IOP RESOURCES

Astrophysicists have discovered an ‘extraordinarily inflated’ low-density exoplanet. KELT-11b has a radius around 1.4 times that of Jupiter but only about a fifth of its mass, giving it a density of only 0.09 g/cm 3, around the density of Styrofoam. KELT-11b orbits close to its parent star and has an orbital period of just five days. The parent star is in the process of expanding into a red giant and is likely to engulf its low-density satellite within a hundred million years.


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