Oscar Duhalde and the Discovery of Supernova 1987A


By Emily LevesqueUniversity of Washington

At around 2 am on 24 February 1987, a Chilean engineer named Oscar Duhalde stepped outside, taking a break from a long evening’s work to look up at a sparkling sky of stars. But Oscar was a decidedly unusual night shift worker, and what he saw in the sky on that night would mark a unique moment in living human history.

An image of 1987A supernova remnant
According to some estimations, supernovae occur in our neighborhood once or twice a century. (Image: NASA, ESA, and R. Kirshner/Public domain)

Oscar Duhalde’s Discovery

Oscar was a telescope operator at Las Campanas Observatory in Chile. Telescope operators typically work at a specific observatory and are trained scientists and engineers who specialize in the immensely complex operations of the world’s best and largest telescopes. Oscar was a seasoned telescope operator and had spent nearly two decades learning the ins and outs of telescopes, working with the astronomers who visited the observatory, and learning the Southern Hemisphere sky in great detail. 

This meant that when Oscar looked up on the night of February 24th, he immediately noticed something unusual. The Large Magellanic Cloud had an extra star in it. Oscar knew this was unusual, but it would be several hours before he and his colleagues fully understood what he’d seen. 

The strange new star in a neighboring galaxy would spark a worldwide fervor among astronomers, and usher in an era of astronomy not seen since the 17th century. It would also give Oscar a unique place among astronomical heroes. He had become one of only a handful of people in human history to discover a supernova with the naked eye.

The Location of the New Star

An image of 1987A supernova within the Magellanic Cloud
Supernova 1987A was located in the Large Magellanic Cloud, 160,000 light-years away from earth. (Image: NASA/Ames Research Center/Public domain)

Oscar’s small new star was in a corner of the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This supernova happened over 160,000 light-years away, 10 to 20 times farther away than Kepler’s Supernova and Tycho’s Supernova. The distance meant that the supernova could have been easy to miss for someone who wasn’t as familiar with the night sky as Oscar.

Oscar checked on what he was seeing again and again as he sipped his coffee that night. It wasn’t a plane, a satellite, or some trick of the night sky. He knew the Large Magellanic Cloud practically by heart and knew this star was a new addition. 

By 1987, supernovae were a known phenomenon in astronomy, and Oscar knew that astronomers had been searching other galaxies for signs of them. Most searches focused on enormous galaxies with heaps of stars that might be ready to die, rather than smaller galaxies like the Large Magellanic Cloud. Still, it was an intriguing possibility.

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The Appellation of Supernova 1987A

Later that evening, another astronomer on the mountain named Ian Shelton noticed the same strange new star when he was reviewing glass photographic plates from the night. When Shelton mentioned his discovery, Oscar recalled his early naked-eye observation. 

An entire region around supernova 1987A
The name 1987A indicates the year that the supernova was discovered and implies that the supernova was the first one to be discovered that year. (Image: NASA Goddard Space Flight Center from Greenbelt, MD, USA/Public domain)

Together, they compiled and sent out an announcement to their fellow astronomers, setting off a storm of activity and excitement at this bright new supernova, dubbed 1987A—named for the year it was spotted, and given the designation of A to mark it as the first supernova observed that year. In the years since, supernova 1987A has become one of the most famous and well-studied supernovae of all time.

Where Are All the Milky Way Supernovae?

Astronomers estimate that there should be one or two supernovae in our neighborhood every century. Some supernovae have likely happened in our galaxy during the last few hundred years, but they may have been blocked from our view by our galaxy’s dense star- and dust-filled disk. A simple quirk of statistics puts us where we are today, with no local observable supernovae in our own Milky Way for over 400 years. 

That said, it is fun to imagine what it would look like if you were to step outdoors tonight, look up, and spot the next Milky Way supernova. The sight of a sudden new light in the sky, appearing as if from nowhere and getting brighter and brighter, might look a bit alarming at first. 

Once it got identified as a supernova, it would become a global source of excitement, covered by everyone from national news anchors to social media hashtags. Today, astronomers have developed telescopes and software that can do, computationally, what Oscar did with his eyes and mind, detecting supernovae up to billions of light-years away.

Common Questions about Oscar Duhalde and the Discovery of Supernova 1987A

Q: Who was Oscar Duhalde?

Oscar Duhalde was a Chilean engineer and a telescope operator at Las Campanas Observatory. On 24 February 1987, while stepping out during his break time, Oscar noticed something unusual in the Magellanic Cloud. The new star was later proved to be a supernova, and Oscar was one of the few astronomers making this great discovery with the naked eye.

Q: Where was the location of the newly discovered star by Oscar Duhalde?

Supernova 1987A was located in a corner of the Magellanic Cloud. It also happened more than 160,000 light-years away, many times further away than Tycho’s and Kepler’s Supernovae. Oscar Duhalde knew the night sky by heart and that’s why he could spot this very distant supernova.

Q: Why was the supernova discovered by Oscar Duhalde named supernova 1987A?

After Oscar Duhalde observed the new star in the Magellanic Cloud, Ian Shelton, who was another astronomer noticed it that evening. Shelton and Oscar announced their fellow astronomers to study the new bright supernova. They gave it the name 1987A for being the first supernova to be discovered that year.

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