PREVIEW

It’s one of the most dazzling sights in the cosmos — and now the spectacular Butterfly Nebula has been captured in extraordinary detail to mark a major milestone for one of the world’s leading observatories.

To celebrate 25 years since the completion of the International Gemini Observatory, students in Chile were given the chance to vote for a celestial target. Their choice was NGC 6302, a vast, fiery planetary nebula that looks uncannily like a butterfly bursting through space.

The winning image was snapped by the Gemini South telescope, the 8.1-metre giant perched atop Cerro Pachón in Chile and operated by NSF NOIRLab with funding from the U.S. National Science Foundation. The shot forms part of the Gemini First Light Anniversary Image Contest, an initiative inviting students in the observatory’s host communities to help celebrate its legacy since Gemini South first opened its ‘eyes’ in November 2000.

NGC 6302 is a bipolar planetary nebula sitting between 2,500 and 3,800 light-years away in the constellation Scorpius. While its official name is NGC 6302, it’s far better known by its dramatic nicknames — the Butterfly Nebula, the Bug Nebula, or Caldwell 69. Credit for its discovery is usually given to American astronomer Edward E. Barnard, who studied it in 1907, though some historians argue it may have been spotted as early as 1826 by Scottish astronomer James Dunlop.

Despite the name, a planetary nebula has nothing to do with planets. It forms when a dying star blows off its outer layers, creating a glowing shell of ionised gas. Early astronomers thought these roundish shapes looked planet-like through their telescopes — and the name stuck. But nothing about the Butterfly Nebula looks round. Instead, immense wings of gas stream outward as if a cosmic creature has taken flight, driven by the violent evolution of the star at its centre.

In 2009, NASA’s Hubble Space Telescope confirmed that the central star of NGC 6302 is a white dwarf — an ultra-dense remnant of a Sun-like star that shed its outer layers more than 2,000 years ago. Despite being only two-thirds the mass of our Sun, it boasts a staggering surface temperature of over 250,000°C (450,000°F), making it one of the hottest stars ever recorded.

Before collapsing into a white dwarf, the star ballooned into a red giant nearly 1,000 times the size of the Sun. As it aged, it expelled its outer layers in two dramatic phases: slow-moving gas that formed a dark, doughnut-shaped ring around the star, and faster material blasting outward along its poles. This ring acted like a cosmic funnel, sculpting the spectacular dual wings visible today.

The dying star then unleashed a ferocious stellar wind tearing through the nebula at more than three million kilometres per hour (1.8 million mph). Collisions between slow and fast gas carved the nebula into its present form, full of ridges, folds, and towering pillars.

Now scorching hot and brilliantly bright, the white dwarf continues to energise the nebula, heating its wings to over 20,000°C (35,000°F). The rich red hues in the image reveal glowing hydrogen gas, while the vivid blues mark highly ionised oxygen. Alongside elements such as nitrogen, sulfur, and iron, this material will eventually help form new stars and planets.