{♫Intro♫}
You’ve probably heard Carl Sagan’s famous
saying that “we’re made of starstuff.”
And it’s true!
Aside from hydrogen—which was created right after the Big Bang—
basically everything inside your body was once part of a star
that burst in a supernova explosion and blasted
its contents across the universe.
But supernovas don’t just spew elements
that have already formed within the star—
the extreme forces within the blast
can forge new elements in an instant,
during the explosion itself.
And this week, we got our best look yet
at how that process can create huge amounts of calcium—
the same stuff that’s in our bones and teeth.
In a paper published this week in The Astrophysical Journal,
an international team described a recently discovered blast
that turned out to be a rare calcium-rich supernova.
These supernovas are fascinating
because they’re extremely uncommon,
yet astronomers estimate
that they’re responsible for around half the calcium in the universe.
The thing is, no one knew how any of them
produced such large amounts of calcium
—until now.
This blast was first discovered in April 2019
by an amateur astronomer in Seattle,
looking through his new telescope.
He noticed a bright spot in M100,
a beautiful spiral galaxy about 50 million light-years away.
After reporting his potential supernova discovery to the pros,
it took just hours for telescopes around the world
and in space to focus on this spot
and begin making their own observations.
It was a supernova, and since they’d acted so quickly,
astronomers were able to start observing it just 10 hours
after it exploded.
And that early start paid off.
In the first few days,
NASA’s Swift space telescope caught something unexpected:
bright X-ray emissions,
which disappeared just five days after the explosion.
The existence of such bright X-ray emission
for that short period of time led the research team
to suspect that the death of this particular star happened in two phases.
At first, the star’s outer layers probably just drifted away into space,
which happens sometimes as a massive star becomes unstable.
Then, when the core exploded,
the blast of energy superheated that loose material,
emitting X-rays.
Along the way, it formed tons of calcium—
in fact, more calcium than astronomers
have ever observed in a single astronomical event.
And that formation happened with astonishing speed.
The extreme energy of the explosion
drove chemical reactions that generated
as much calcium as regular stars typically do
over billions of years.
As for what actually exploded, though, that’s still a mystery.
Astronomers looked through old images from Hubble,
which has studied this galaxy frequently
over the last 25 years, hoping to identify the star that exploded.
But they didn’t find it.
That means the star must have been
pretty small and dim—possibly a white dwarf,
which is the leftover remains of a star
that is no longer burning fuel.
Whatever it was, the end result was a lot of brand-new calcium for the universe.
That wasn’t the only supernova news
we’ve gotten recently.
In another pair of papers published last week
in The Astrophysical Journal,
astronomers described observations that may
finally point towards the remains of the star that created
the famous supernova 1987A.
It’s hard to overstate how important this supernova has been for astronomy.
It exploded just 168 thousand light-years away in the Large Magellanic Cloud.
Thousand is not a number we talk about in astronomy very often!
And when it was discovered in 1987,
it was not only the brightest supernova
in hundreds of years,
but also the first nearby one
since the development of modern astronomy.
That means that this explosion has been studied
in excruciating detail since the day its light reached Earth.
Hubble alone has made hundreds of observations
over the course of three decades.
And yet, in all that time,
no one was ever able to spot what had happened to the dead
star’s core… which is odd.
See, supernova 1987A showed the clear signature
of a core-collapse supernova,
in which the star’s core crunches down into either
a neutron star or a black hole.
Astronomers suspected it had formed a neutron star,
since they’d detected lots of neutrinos,
which are associated with these stars,
but they couldn’t see anything through the debris
surrounding the explosion.
They even thought maybe the core had collapsed
all the way into a black hole after all.
But recently, thanks to data from the giant ALMA radio telescope in
Chile’s Atacama Desert,
astronomers uncovered the first clear evidence
that it’s there.
In 2015, ALMA detected a blob
of super hot material
surrounding the location where the
neutron star ought to be.
The blob was so bright that at first
the research team thought it couldn’t possibly be heated
by a neutron star.
But theoretical work laid out in the second paper shows that that isn’t true.
We just haven’t ever seen a neutron star this young before.
At just 33 years old,
it’s ten times younger than the
next-youngest one studied closely by astronomers,
making it hotter and brighter
than anything we’ve seen before.
And that’s why it’s able to heat up the
surrounding debris as much as it does.
Astronomers will probably have to wait
for the supernova’s dust to settle a bit more
before they can see the neutron star itself
and put this decades-long mystery to bed.
That might still take a few more decades,
but, in the meantime, we’ll keep watching
the life story of this supernova play out
in unprecedented detail, one observation at a time.
Thanks for watching this episode of SciShow Space News!
And a special thank you to our
President of Space, Faisal Saud.
Thank you!
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We wouldn’t be here without you!
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{♫Outro♫}