Two's company: Scientists identify new class of star remnants

In about 5 to 8 billion years, our sun is expected to evolve into a white dwarf—an extremely dense, Earth-sized stellar remnant that has exhausted its fuel and shed its outer layer. But while our sun is a solitary star, research over the past 15 years has demonstrated that binary or multi-star systems are far more common than astronomers once thought. When a dense and compact remnant like a white dwarf is involved in a binary system, it often "snatches away" material from its companion star. This process, called accretion, usually emits X-rays in what is considered a "signature" signal.