Searching for Earth-like exoplanets, astronomers usually search for worlds around a kind of star called a red dwarf on an M dwarf. These star types are somewhat like our sun and are common in our galaxy, accounting for about 70% of the stars. New research shows, however, that rocky exoplanets in orbit may have another star type, a white dwarf, an interior that is surprisingly similar to our planet.
White Dwarves are shrunken remains of once bright stars with extremely strong gravity. Normally, this gravity means that the surface of the stars consists of light elements such as hydrogen and helium. In some cases, however, there are also "polluted" white dwarfs whose atmosphere contains heavier elements such as magnesium, iron and oxygen. These elements are introduced to the White Dwarf when a rocky exoplanet bumps against the star, providing astronomers with proof of how the exoplanets were before they were destroyed.
"By observing the White Dwarfs and the elements present in their atmosphere, we are watching the elements in the body orbiting the White Dwarf," said Alexandra Doyle, a Ph.D. student at the Institute of Earth, Planetary and Space Sciences of the United States University of California at Los Angeles, in a statement. "The great attraction of the White Dwarf shreds the asteroid or the planetary fragment that surrounds it, and the material falls on the White Dwarf." Planets orbiting them earlier. "If I only looked at a white dwarf star, I would expect hydrogen and helium," Doyle said. "But in this data, I also see other materials like silicon, magnesium, carbon, and oxygen ̵
The surprising finding here was how similar the exoplanets were were on Earth under their rocky outlines. "How similar are the rocks analyzed by the researchers to the rocks of Earth and Mars? Very similar, "said Doyle. "In terms of their oxidized iron, they are earth-like and Mars-like. We find that rocks are rocks everywhere, with very similar geophysics and geochemistry.
The research was published in the journal Science.