Southern Ring Nebula’s Spokes (NIRCam and MIRI Composite Image)

Examine the straight, brightly-lit lines that pierce through the rings of gas and dust around the edges of the Southern Ring Nebula in the Webb Space Telescope’s image. These “spokes” appear to emanate from one or both of the central stars, marking where light streams through holes in the nebula. The holes are evidence of where the dimmer star that created this scene shot out material, creating open pathways for light to flow through.

Some of the star’s ejections followed thin, straight lines (second box) through the gas and dust. Other ejections (first box) look bent, curvy, and thicker. Why? A team of researchers, led by Orsola De Marco of Macquarie University in Sydney, Australia, modeled how these complex structures might have formed. Studies of planetary nebulae have shown that even when dying stars eject their gas and dust at all angles simultaneously, the outflowing gas may not stay symmetrical for long. In the Southern Ring Nebula, the team projects that the straight lines may have been shot out hundreds of years earlier and at greater speeds than those that appear thicker and curvy. It’s possible the second set is a mix of material that slowed, creating less linear shapes.

By carefully comparing the appearance and timing of these ejections in the data and simulations, De Marco and her team propose that this is more evidence of the presence of a star with a slightly wider orbit that “stirred the pot” of ejections.

This image combines near- and mid-infrared light. The dimmer star that created the planetary nebula appears as a faint red star next to the central blue star.