The "Death Star", which the Sun will turn into in a few billion years, is likely to first destroy the Moon and then the Earth. A study by scientists from the Harvard-Smithsonian Center for Astrophysics (Cambridge, Massachusetts, USA) and the University of Warwick (Coventry, UK) is published at arXiv.org.
In their work, astronomers have studied the effect on the content of heavy elements in the atmosphere of white dwarfs, into which sun-like stars, satellites of planets orbiting the stars, turn over time. About a quarter of such luminaries are contaminated with fragments from a disk rotating around them, consisting of fragments of planetary bodies.
Scientists explain the frequent replenishment of this disk by the destruction of exoplanet satellites. The moons of exoplanets revolving around white dwarfs are more intensely attracted by the stars than massive celestial bodies. If the distance between the white dwarf and the companion becomes less than a few tenths of the Hill's radius, the risk of the moon being destroyed by the star's gravity increases dramatically.
As previously made estimates have shown, a million years is enough for the space around the white dwarf to become overgrown with fragments of satellites and planets with a mass comparable to Pluto. These elements, falling on the star, lead to a change in its observed spectrum.
The white dwarf WD 1145 + 017, located 570 light-years from Earth in the constellation Virgo, has attracted the attention of scientists most recently. Its age is estimated at 175 million years. Scientists believe that in a few billion years, the Sun will become a red giant and swallow up Mercury, Venus, and probably also Earth and Mars. Subsequently, the luminary will turn into a white dwarf and, like WD 1145 + 017, will begin to destroy objects around it.