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[♪ INTRO]
A big part of astronomy is trying to organize the amazing diversity of the universe
into categories to help us make sense of what’s out there.
But sometimes, things don’t fit cleanly into one bucket or another, like brown dwarfs.
These objects can be tens of times larger than gas giants like Jupiter, but are
too small to generate the pressure needed for the nuclear fusion that powers stars.
So, they kind of exist as oddballs in-between.
And even among a collection of oddballs, sometimes there’s an object
that is so weird astronomers hardly recognize it.
That was the case for one recently-discovered brown dwarf, and a paper published
this summer in the Astrophysical Journal Letters tries to unpack just how
it could look so wrong.
Turns out, the answer to that takes us back to the beginning of the cosmos.
Although brown dwarfs don’t make light through nuclear fusion, they do shine faintly
in the infrared, radiating heat energy left over from their formation.
That emission generally follows a pattern, with certain parts of the infrared spectrum
shining brighter than others.
Which parts are bright and which are dim change as the brown dwarf cools during its life.
But one brown dwarf about 50 light-years away seems to break these conventions.
It’s nicknamed “The Accident”, which sounds more like the name
of a clumsy pro wrestler than an astronomical object, but let’s not split hairs.
It’s called that because it was discovered, well, by accident,
by a citizen scientist looking at images from NASA’s WISE telescope.
What makes The Accident unique is that its infrared spectrum has features
that correspond to both hot, young brown dwarfs and old, cool ones.
Also, while making follow-up observations, the paper’s authors realized
that it’s zooming through space at around 800,000 kilometers per hour!
That’s way faster than other brown dwarfs astronomers have studied at this distance,
but this speed might also be the key to understanding The Accident’s appearance.
This object could have picked up speed through gravitational interactions with nearby stars.
But to get going that fast, it would’ve needed a bunch of run-ins like this.
And that suggests that this brown dwarf is incredibly old.
Like, the researchers estimate it could be as much as 10 to 13 billion years old;
at least twice as old as average brown dwarfs.
Back then, the Milky Way was a young galaxy, made almost entirely
of hydrogen and helium gas.
That means, if The Accident formed back then, it too would be
mostly hydrogen and helium.
And that could help explain its infrared spectrum.
See, most brown dwarfs contain a healthy dose of methane,
but that gas didn’t exist in the galaxy 13 billion years ago.
So, if The Accident is that old, it’s no surprise that it just doesn’t follow
the light patterns typical of younger brown dwarfs: It has a different composition.
And the research team thinks it might not be alone, either.
Brown dwarfs as dim as this have to be somewhat close to Earth for us to see them,
but there might be more just out of view.
A funny-looking brown dwarf wasn’t the only strange observation
astronomers described recently.
Last week, in a paper published in the journal Science, a team also described
a radio wave emission called VT 1210+4956.
And while it might lack a super sweet fighter name, its presence suggests scientists
may have finally found a type of supernova that had been predicted by theory.
Specifically, the team describes how this signal may be the result of a star
having its heart basically punched out by another object.
VT 1210 is a radio wave emission from the outer region of a dwarf galaxy
480 million light-years away.
It was first spotted in a recent image from the Very Large Array radio telescope, or VLA.
But when researchers looked back at VLA observations from the late ‘90s
and early 2000s, it wasn’t there.
With follow-up observations, though, the authors were able to piece together
a remarkable story about how this burst came to be.
It started with a pair of giant stars, orbiting each other.
When the first reached the end of its life, it exploded in a supernova,
leaving behind only its core.
Depending on the exact size of the star, that core could be either a black hole
or a super dense object called a neutron star.
Astronomers use the catch-all term compact object to describe
those different possibilities.
Either way, that compact object started to spiral closer and closer to its companion,
until it began to dip into the remaining star’s outer layers.
As it did, it began to spray the star’s insides into space, which caused
the compact object to dive even deeper.
Eventually, the object got close enough for its gravity to tear apart the star’s core.
And at that point, the end was near.
Nuclear fusion in a star’s core is what creates the energy needed to keep the star
from collapsing in on itself.
So, with that gone, the second star also collapsed in a massive supernova,
hurling what was left of itself into space.
That material traveled out at nearly the speed of light, where it collided with the star’s
outer layers, which had already been kicked out when the compact object first entered.
And it’s this collision that produced the radio waves picked up by the VLA.
This event was a stellar assassination of the highest order.
And although models had predicted things like this might happen,
this is the first time astronomers have seen evidence for it in real life.
It’s a reminder that the universe is chock-full of gruesome ways for things to end,
and we’ve still got plenty of categories left to uncover.
But something we don’t want to end as we know it due to climate change is our home,
Earth.
One tool to tackle the climate crisis together is Wren.
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Once you sign up to make a monthly contribution to offset your carbon footprint,
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Then, you get a personalized report that estimates your carbon footprint.
You’ll also receive monthly updates from the tree planting, rainforest protection,
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As a bonus, we’ve partnered with Wren to plant 10 extra trees for the first 100 people
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And as always, thanks for supporting SciShow Space.
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