Exploding Stars are Titanium Factories

Titanium, shaded in blue, superimposed on observations of the supernova Cas A. Image credit: Chandra: NASA/CXC/RIKEN/T. Sato et al.; NuSTAR: NASA/NuSTAR; Hubble: NASA/STScI

If you’re a fan of titanium, you should head to the nearest supernova. You’ll get more than enough of it. And its presence can help astronomers understand how supernovae work.

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The Debris Cloud From a Supernova Shows an Imprint of the Actual Explosion

Computer models are continuing to play an increasing role in scientific discovery.  Everything from the first moments after the Big Bang to potential for life to form on other planets has been the target of some sort of computer model.  Now scientists from the RIKEN Astrophysical Big Bang Laboratory are turning this almost ubiquitous tool to a very violent event – Type Ia supernovae.  Their work has now resulted in a more nuanced understanding of the effects of these important events.

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An All-Sky X-Ray Survey Finds the Biggest Supernova Remnant Ever Seen

Composite Image of radio and x-ray observations of the Hoinga Supernova Remnant Credit: eROSITA/MPE (X-ray), CHIPASS/SPASS/N. Hurley-Walker, ICRAR-Curtin (Radio)

Our sky is missing supernovas. Stars live for millions or billions of years. But given the sheer number of stars in the Milky Way, we should still expect these cataclysmic stellar deaths every 30-50 years. Few of those explosions will be within naked-eye-range of Earth. Nova is from the Latin meaning “new”. Over the last 2000 years, humans have seen about seven “new” stars appear in the sky – some bright enough to be seen during the day – until they faded after the initial explosion. While we haven’t seen a new star appear in the sky for over 400 years, we can see the aftermath with telescopes – supernova remnants (SNRs) – the hot expanding gases of stellar explosions. SNRs are visible up to a 150,000 years before fading into the Galaxy. So, doing the math, there should be about 1200 visible SNRs in our sky but we’ve only managed to find about 300. That was until “Hoinga” was recently discovered. Named after the hometown of first author Scientist Werner Becker, whose research team found the SNR using the eROSITA All-Sky X-ray survey, Hoinga is one of the largest SNRs ever seen.

Composite of the X-ray (pink) and radio (blue) image of Hoinga. The X-rays discovered by eROSITA are emitted by the hot debris of the exploded progenitor star. Radio antennae on Earth detect radiation emission from electrons in the outer shell of the supernova
Credit: eROSITA/MPE (X-ray), CHIPASS/SPASS/N. Hurley-Walker, ICRAR-Curtin (Radio)
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A New Study Says That Betelgeuse Won’t Be Exploding Any Time Soon

Computer simulation of Betelgeuse in all its Red Supergiantyness - C. Space Engine Pro by Author

I have stood under Orion The Hunter on clear evenings willing its star Betelgeuse to explode. “C’mon, blow up!” In late 2019, Betelgeuse experienced an unprecedented dimming event dropping 1.6 magnitude to 1/3 its max brightness. Astronomers wondered – was this dimming precursor to supernova? How cosmically wonderful it would be to witness the moment Betelgeuse explodes. The star ripping apart in a blaze of light scattering the seeds of planets, moons, and possibly life throughout the Universe. Creative cataclysm.

Only about ten supernova have been seen with the naked eye in all recorded history. Now we can revisit ancient astronomical records with telescopes to discover supernova remnants like the brilliant SN 1006 (witnessed in 1006AD) whose explosion created one of the brightest objects ever seen in the sky. Unfortunately, latest research suggests we all might be waiting another 100,000 years for Betelgeuse to pop. However, studying this recent dimming event gleaned new information about Betelgeuse which may help us better understand stars in a pre-supernova state.

This comparison image shows Betelgeuse, before and after its unprecedented dimming
ESO / M. Montargès et al.
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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)
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

The red supergiant Betelgeuse. Its activity can be confounding, and new research suggests that the star could've consumed a smaller companion star. Image credit: Hubble Space Telescope. Image Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella

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

Visible, infrared, and X-ray light image of Kepler's supernova remnant (SN 1604) located about 13,000 light-years away. Credit: NASA, ESA, R. Sankrit and W. Blair (Johns Hopkins University).

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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Gravitational waves could show what’s happening inside a star as it’s going supernova

A 2-D snapshot of a pair-instability supernovae as the explosion waves are about to break through the star's surface. The tiny disturbances represent fluid instability - in a region where different elements interact and mix. Image Credit: ASIAA/Ken Chen

It’s kind of hard to see inside a star as it’s blowing up, because of the whole “blowing up” part, but gravitational waves – tiny ripples in the fabric of spacetime itself – may help astronomers unlock how the biggest stars die.

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