Doomed exoplanets were much like Earth

Some rocky exoplanets bear a striking resemblance to Earth, according to Alexandra Doyle, Edward Young and colleagues at the University of California at Los Angeles. The team used the properties of light coming from six white-dwarf stars to calculate how much oxygen, iron and other elements were present in planets that once orbited the stars. Their observations suggest that these planets – which were consumed by their stars long ago – have the same geophysical and geochemical properties as Earth. While astronomers are able to observe rocky exoplanets, working out what they are made of is difficult and this research provides important clues regarding the composition of these Earth-like objects.