Astronomers have discovered a binary star system with the closest high-mass young stellar objects ever measured, providing a valuable “laboratory” to test theories on high mass binary star formation.

An international team led by the University of Leeds has determined the distance between the massive young star PDS 27 and its orbiting stellar companion to be just 30 astronomical units away or 4.5 billion km. That is roughly the distance between our Sun and Neptune, making them the stellar companions with the closest proximity ever determined for young high mass stars in a binary system – a star system with two stars in orbit around a centre of mass.

Study lead author, Dr Evgenia Koumpia, from the School of Physics and Astronomy at Leeds, said: “This is a very exciting discovery, observing and simulating massive binaries at the early stages of their formation is one of the main struggles of modern astronomy. With PDS 27 and its companion we have now found the closest, most massive young stellar objects in binaries resolved to date.

“There is a shortage of known young massive binary systems in charted space. High mass stars have comparatively short lifespans, burning out and exploding as supernovae in only a few million years, making them difficult to spot. This limits our ability to test the theories on how these stars form.”