Using the James Webb Space Telescope and data from Chile’s Very Large Telescope, an international astronomy team has uncovered extraordinary images of a rare stellar system called Apep, showing four distinct dust shells spiralling outward from three massive stars locked in a cosmic dance.
‘Wolf-Rayet’ stars are a rare class of massive binary stars, where the earliest carbon in the universe is forged notes the Australian Science Media Exchange. The discovery helps astronomers understand how these stars interact and evolve over centuries.
A paper by Macquarie University masters student Ryan White, published in The Astrophysical Journal, has refined the orbit of the Wolf-Rayet stars in the Apep system, by combining precise measurements of the ring location from JWST’s image with the speed of the shells’ expansion from observations taken by the VLT over eight years.
JWST observations delivered a first of its kind: a crisp mid-infrared image of a system of four serpentine spirals of dust, one expanding beyond the next in precisely the same pattern. Ground-based telescopes had only detected one shell before JWST revealed all four.
The two Wolf-Rayet stars were initially more massive than their supergiant companion, but have shed most of their mass. Eventually, the Wolf-Rayet stars will explode as supernovae, quickly sending their contents into space.
Of the few hundred Wolf-Rayet binaries that have been observed to date, Apep (named for the Egyptian god which the dust pattern resembles) is the only example that contains two Wolf-Rayet stars of these types in our galaxy; most only have one.