A system with several stars and an atypical dust disk has been discovered by astronomers. The observation confirms the theory that a disk can rotate perpendicular to the orbit of two central stars.
An incredible solar system was discovered 150 light years from Earth. The structure named HD 98800, which was so far purely hypothetical, has just been observed by astronomers thanks to the ALMA radio telescope installed in Chile.
The team of astrophysicists presented their discovery on January 14, 2018 in the journal Nature Astronomy. They explain that HD 98800 is composed of two pairs of stars: one of them is inside the disc, the other outside.
But this is not the most surprising fact about the system: it is the inclination of the disc that has attracted the attention of scientists. Indeed, the dust disk rotates perpendicularly to the orbit of the two stars at its center. This configuration is different from our solar system, in which the objects are on the same plane as the orbit of the Sun, a system is referred to coplanar.
“Until now, this configuration existed only in the minds of theorists,” warns the University of Warwick in a statement.
The HD 98800 disc is also protoplanetary. This means that it is made up of gas and dust. From these clouds, matter is collected to give birth to planets, their satellites and other small bodies.
The presence of a circumstellar disk was suspected to exist in the HD 98800 system since the 1980s. In the 90s, another study had suggested that the disc had to be coplanar – located in the same plane as that of the central star orbit. But the new study contradicts this. During its formation, the disc could have been misaligned with the “horizontal binary plane” of the stars in its center. Two scenarios were then possible: a coplanar system or a perpendicular configuration (called “polar”).
Previous works have revealed the existence of coplanar discs revolving around 2 stars. However, before HD 98800 “no polar example was known,” the scientists write.
In the HD 98800 disc, scientists finally note similarities with those surrounding the lonely stars and wonder of planets someday be formed there. “We may still have to discover a whole population of planets” moving perpendicular to the orbit of 2 stars, conclude the authors.