Supernova 1987a, also known by its designation SN1987A, is a type II supernova that occurred in the Large Magellanic Cloud some 168,000 light-years away from Earth. The light from 1987a reached Earth on February 23, 1987, becoming the first discovered supernova of the year and the closest one ever observed since Kepler’s Supernova in 1604. Ian Shelton discovered SN1987A while at the Las Campanas Observatory in Chile, while Albert Jones observed it from New Zealand within 24 hours after. Researchers performed follow up observations using the Astron Ultraviolet Space Telescope, the greatest of its kind in orbit at the time.

A supernova occurs at the end of a star’s life cycle. As a star bursts into a dazzling spectacle of light, the newly born supernova creates elements that form the building blocks of future stars, planets, and even life, leaving traces of evidence such as the iron found in a person’s blood. During the event that created SN1987A, an estimated 20,000 Earth masses worth of radioactive iron released into the Cosmos, like seeds dispersed in the wind creating new worlds and stars within the 160,000 year window when its light finally reached Earth.    

Direct observations and study of SN 1987A over the past decades resulted in a significant understanding of how massive stars behave at their demise. NASA’s Hubble Space Telescope’s pristine images proved pivotal in allowing scientists to analyze this wondrous phenomenon. Launched three years after the discovery of 1987a, Hubble’s sharp imaging allows researchers to continue yielding results and scientific breakthroughs far greater than ever imagined at the time of the supernova’s discovery. Prior to 1987, scientific consensus regarding exploding stars insisted that such explosions bore a spherical structure, instead of the revelation of millennia old gas and debris emitted from this dying star that caused the rewriting of textbooks.

Supernova 1987a deep within the Large Magellanic Cloud, a dwarf galaxy satelite of the Milky Way. Credits: NASA/STScl

Among a plethora of scientitic discoveries, Hubble revealed a glowing ring nearly a light-year in diameter that was present around the star some 20,000 years before it exploded. The supernova event caused x-rays to energize the ring, making it glow bright enough to illuminate the surrounding areas and offer astronomers a unique observational opportunity as the whole ring becomes completely illuminated in the years to come.

SN1987A remains the best supernova ever studied by mankind, with a forecast offering a trove of astounding information destined to redefine everything we known about the final stages of a star’s lifecycle. In a galaxy the size of the Milky Way with hundreds of billions of stars, astronomers expect a new supernova to appear every 50 years. Studying this phenomenon may lead to a greater understanding of the dynamics of our universe, by studying the light of the past allowing our civilization to illuminate the path into the future.

Supernova 1987a as seen through various instruments. Credit: NASA