Scientists studying the atmosphere’s of White Dwarfs made an interesting announcement recently. After studying the spectra of hot young white dwarfs, scientists from the University of Leicester and the University of Arizona can now speak  more closely to the atmospheres of these objects. For those who are not aware, White Dwarfs are the remnants of Sun like stars. The are comprised of a core of oxygen, nitrogen, and carbon, the byproducts of hydrogen and helium fusion during their lifetime on the main sequence. The core then collapses, to about the size of the Earth, and what is left is a dense core of metals(and astronomical term for anything thats not hydrogen or helium) and a think atmosphere still comprised of hydrogen and helium. But the spectra of these exotic stars atmospheres had led to something strange. Higher contents of metals were observed in the atmosphere than what was expected. Was this due to some convective force bringing up material from the White Dwarf’s core, or was there some other source for the metals being observed in the atmosphere. 

According to the new research. It turns out that the source of these metals seem to be rocky planets. The levels of Carbon, Silicon, and Iron detected is exactly what you would expect if the star was absorbing earth like planets, and it seems that is indeed what they are doing. This discovery not only leaves us with an interesting end game for earth, but also provides us with a new tool for the fate of the earth. According to most calculations anyway, the earth will be destroyed by the Sun long before the Sun becomes a White Dwarf, but whether our precious metals stick around in the Sun’s atmosphere is a topic of debate. This discovery however, allows us to study the composition of extrasolar rocky planets like we have never before. Rocky planets as we now know are very common in the universe, but they are so small that it is hard to confirm their existence in faraway galaxies. Even after detecting them, knowing their composition is an entirely different matter. Stars compositions have long been studied using their spectra, or certain wavelengths of light that are absorbed and emitted from elements switching through energy states, but for rocky planets, this is impossible. First, no one has directly imaged a terrestrial exoplanet, and even if you could, you probably wouldn’t see much besides atmospheric spectra. Now by studying the atmosphere of white dwarfs, fairly common in the Galaxy, we can now tell the internal compositions of faraway terrestrial planets, which in turn allows us to compare with our own terrestrial planets and further our understanding of Solar Systems and the planets inside them.

http://www.sciencedaily.com/releases/2014/03/140326092240.htm