Astronomers Think They’ve Found the Neutron Star Remnant Left Behind from Supernova 1987A

It was the brightest supernova in nearly 400 years when it lit the skies of the southern hemisphere in February 1987. Supernova 1987A – the explosion of a blue supergiant star in the nearby mini-galaxy known as the Large Magellanic Cloud – amazed the astronomical community. It offered them an unprecedented opportunity to observe an exploding star in real-time with modern instruments and telescopes. But something was missing. After the supernova faded, astronomers expected to find a neutron star (a hyper-dense, collapsed stellar core, made largely of neutrons) left-over at the heart of the explosion. They saw nothing.

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A New Supernova Remnant Found from an Exploding White Dwarf Star

Astronomers have spotted the remnant of a rare type of supernova explosion. It’s called a Type Iax supernova, and it’s the result of an exploding white dwarf. These are relatively rare supernovae, and astronomers think they’re responsible for creating many heavy elements.

They’ve found them in other galaxies before, but this is the first time they’ve spotted one in the Milky Way.

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There Should be a few Supernovae in the Milky Way Every Century, but we’ve Only Seen 5 in the Last 1000 Years. Why?

This image of the supernova remnant SN 1987A was taken by the NASA/ESA Hubble Space Telescope in January 2017 using its Wide Field Camera 3 (WFC3). Since its launch in 1990 Hubble has observed the expanding dust cloud of SN 1987A several times has helped astronomers get a better understanding of these cosmic explosions. Supernova 1987A is located in the centre of the image amidst a backdrop of stars. The bright ring around the central region of the exploded star is material ejected by the star about 20 000 years before the actual explosion took place. The supernova is surrounded by gaseous clouds. The clouds’ red colour represents the glow of hydrogen gas. Image Credit: NASA, ESA, and R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) and P. Challis (Harvard-Smithsonian Center for Astrophysics)

Our galaxy hosts supernovae explosions a few times every century, and yet it’s been hundreds of years since the last observable one. New research explains why: it’s a combination of dust, distance, and dumb luck.

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Wow, Betelgeuse Might Be 25% Closer than Previously Believed

In the last year, Betelgeuse has experienced two episodes of dimming. Normally, it’s one of the ten brightest stars in the sky, and astrophysicists and astronomers got busy trying to understand what was happening with the red supergiant. Different research came up with some possible answers: Enormous starspots, a build-up of dust, pre-supernova convulsions.

Now a new study is introducing another wrinkle into our understanding of Betelgeuse. The authors say that Betelgeuse is both smaller and closer than previously thought.

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A Supernova Exploded Dangerously Close to Earth 2.5 Million Years Ago

In its 4.5 billion year history, Earth has had to run the gauntlet. Numerous catastrophes have imperilled the planet, from massive impacts, to volcanic conflagrations, to frigid episodes of snowball Earth. Yet life persists.

Among all of the hazards that threaten a planet, the most potentially calamitous might be a nearby star exploding as a supernova.

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The Solar System has been Flying Through the Debris of a Supernova for 33,000 Years

An Ancient Voyage

Earth is on a journey…

While our planet orbits the Sun each year – a billion kilometers – our entire Solar System is drifting through the Milky Way Galaxy making one rotation every 225-250 million years (that means dinosaurs actually lived on the other side of the Galaxy!) Humanity has been on Earth for a small fraction of that journey, but parts of what we’ve missed is chronicled. It is written into the rock and life of our planet by the explosions of dying stars – supernova. Turns out supernovas write in radioactive ink called Iron-60.

The Crab Nebula is the remains of a Supernova which occurred about a thousand years ago and was visible on Earth recorded by ancient astronomers – C. NASA/ESA/Hubble

As the Sun travels through the Galaxy, so too do the hundreds of billions of other stars that comprise the Milky Way; all swirling and spiraling in varying directions. If you could time travel to a distant past, you’d look up and see an unfamiliar sky – different stars, different constellations, and sometimes the glow of a brilliant supernova. Stars explode in the Milky Way about once every fifty years. Given the immense size of the Galaxy at around 150,000 light years in diameter, the odds of one of those stars exploding in our backyard is low.  But while supernova happen in the Galaxy twice a century, those in close proximity to Earth, within 400 light years, do happen once every few million years. And along Earth’s epic 4.5 billion-year journey, it appears that we’ve had close encounters with supernova several times. In fact, we seem to be travelling through the fallout cloud of supernovae right now.

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Hubble’s Photo of the Cygnus Loop is, Of Course, Incredible

If you’re a Star Trek fan, you may think the above image portrays the “Nexus” from the movie Star Trek: Generations. In the film, the Nexus was a ribbon-like extra-dimensional realm that exists outside of normal space-time.

But this is actually a real image from the venerable Hubble Space Telescope, of the Cygnus Loop. This stunning picture from space shows just a small portion of a blast wave left over from a supernova that took place, from our vantage point, in the northern constellation Cygnus the Swan.  

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Supernova Wreckage is Still Expanding at Extreme Speeds After 400 Years

Four centuries ago, Johannes Kepler observed a bright new star in the night sky. Astronomers from all over the world noticed it, but it came to be known as Kepler’s star. It was caused by a stellar explosion 20,000 light-years from Earth, and it was the most recent naked-eye supernova to appear in our galaxy.

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The Last Supernovae

A supernova is a powerful event. For a brief moment in time, a star shines as bright as a galaxy, ripping itself apart in a last, desperate attempt to fight against its gravity. While we see supernovae as rare and wondrous things, they are quite common. Based on observations of isotopes in our galaxy, we know that about twenty supernovae occur in the Milky Way every thousand years. These brilliant cosmic flashes fill the universe with heavy elements, and their remnant dust makes up almost everything we see around us. But supernovae won’t keep happening forever. At some point in the far future, the universe will see the last supernova.

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