Detected binary white dwarf system

The Harvard – Smithsonian Astrophysics Center first detected two dead stars orbiting each other and emitting gravitational waves.

At the end of the life cycle, stars of low or moderate mass - like the Sun - consume up their fuel and strip off their outer layers, leaving the core to fade over time called the white dwarfs. Astronomers have long predicted the existence of binary star systems, or binary stars, made up of two such objects. According to the relatively large snow, they can emit energy in the form of gravitational waves, which are ripples or disturbances in the texture of spacetime.

Using a laser interferometer space antenna (LISA), astronomers from the Harvard – Smithsonian Center for Astrophysics (CfA) on April 1 said the first detection of gravitational waves emitted a The binary white dwarf system is about 2,500 light-years from Earth. The star system, named J2322 + 0509, has the third known shortest orbital period, with two helium-white dwarfs orbiting each other every 20 minutes.

Graphic simulating star system J2322 + 0509. Photo: M. Weiss.

"Theories predict that there are many other systems of helium-white dwarfs out there," said astronomer Warren Brown from CfA, the lead author of the study. "This finding has laid the groundwork for exploring similar systems in the future."

J2322 + 0509 is hard to detect. It has no light curve and therefore cannot observe any photometric signals. Instead of looking at light, the team used spectroscopy to observe how matter interacts with electromagnetic radiation, thereby determining the orbital motion of white dwarfs.

Brown adds that J2322 + 0509 will not exist forever as a binary system in the future. The gravitational waves emitted cause its pair of white dwarfs to lose energy. The team estimates that in 6-7 million years, they will orbit and merge into a larger white dwarf star. The research was published in Astrophysical Journal Letters.