Placeholder Image

Subtitles section Play video

  • [♪ INTRO]

  • If you spend any time studying space, you're bound to find some strange stuff;

  • that's one of the best parts about astronomy.

  • But every now and then, even the most experienced scientists

  • find something that makes them scratch their heads.

  • Like Przybylski's Star.

  • We've been studying it since the 1960s,

  • but we still can't seem to figure out what the thing is made of.

  • And according to one study, that might be because it contains elements or isotopes

  • scientists have never seen before.

  • Move over, Tabby's Star, because this might be the weirdest star in the universe.

  • Przybylski's Star is about 370 light-years away,

  • and it's named after the Polish astronomer who first studied it.

  • Przybylski published his first paper about the object in 1961,

  • based on spectroscopy observations.

  • This is a common method that links the type of light a star emits

  • to the elements it contains, among other things.

  • And right away, he knew the observations of this star weren't normal.

  • For one, based on its spectrum, the star seemed to have barely any iron in it, which was weird.

  • Most stars survive by fusing lighter elements into heavier ones,

  • and iron is one of the most common results.

  • On the other hand, this star also seemed to be chock full of lanthanides,

  • even heavier elements like holmium and europium,

  • which normally aren't as abundant in stars.

  • At the time, Przybylski suggested this star must be pretty far along in its lifespan

  • to have produced so many heavy elements.

  • But today, we know the story is a little more complicated than that. Isn't it always?

  • Thanks to lots of scientists and telescope hours,

  • we now know that Przybylski's Star is actually part of a special class called

  • Ap stars, or A-type peculiar stars.

  • Regular A-type stars are usually hot and have no magnetic fields.

  • But Ap stars have cool surfaces, strong magnetic fields, and really long rotation periods.

  • For some reason, these stars also tend to have lots of lanthanides, but not much iron.

  • So in that respect, Przybylski's Star isn't as odd as we first thought.

  • But that doesn't mean it's normal, either.

  • According to a few papers, there's evidence that this star

  • also contains atoms that have no business being there at all.

  • Specifically, ones like promethium and plutonium.

  • These elements and their isotopes, or versions with a different number of neutrons,

  • have relatively short half-lives.

  • This is the time it takes for half of the atoms in a radioactive substance

  • to decay into something else.

  • Promethium, for example, has a half-life of less than 20 years.

  • And plutonium has a half-life of some 24,000 years at most,

  • which is still barely any time at all for a star.

  • That means that, unless they're new additions or are being replenished somehow,

  • they should have all completely decayed by the time humans and telescopes showed up.

  • So far, there are a few possible explanations for this.

  • Some astronomers have suggested that these atoms could have come from a recent supernova,

  • or from ongoing reactions catalyzed by a nearby neutron star.

  • But the evidence for these ideas isn't that strong.

  • You also can't have an astronomy mystery without some alien hypotheses.

  • But, uh, if you have any peer-reviewed papers about that, you can let us know.

  • Still, there's one other possible explanation that doesn't involve First Contact.

  • And if it's true, it would change the textbooks, and not just the astronomy ones.

  • In 2017, in the journal Physical Review A, three researchers suggested that

  • Przybylski's Star might actually contain super heavy elements or isotopes

  • we haven't even discovered yet.

  • And, over time, these super heavy atoms could decay into the short-lived isotopes we've observed.

  • Specifically, they proposed that the atoms could be versions of three elements:

  • flerovium, unbihexium, or unbinilium.

  • We've made really tiny quantities of flerovium in the lab before,

  • like, around 100 atoms total, but we've never seen it in nature.

  • And although we think unbihexium and unbinilium should exist based on what we know about chemistry,

  • we haven't observed them yet.

  • So if this hypothesis is true, it would mean that studying Przybylski's Star

  • would let us see these atoms in the wild, or at all, for the first time!

  • There's even a chance that the isotopes in the star would be part of the

  • island of stability, a hypothetical group of heavy, extra stable elements

  • that scientists have been trying to track down.

  • That would make this star not only important for astronomy,

  • but for chemistry and physics on Earth, too.

  • Now, it is worth mentioning that the team didn't have any new explanation for how

  • those heavy atoms would've gotten there.

  • And there's still a chance we misread the data, and that Przybylski's Star

  • doesn't really contain short-lived isotopes.

  • After all, the spectrum for this star, like the one Przybylski first used to study it,

  • is difficult to read.

  • Normally, spectra have a few fairly clear-cut lines that scientists can link to different elements.

  • But for this star, those lines are kind of all over the place.

  • So there's an ongoing debate about what's going on, because something weird is

  • definitely happening to produce that messy spectrum.

  • One helpful next step would be to take more measurements and hope they're clearer.

  • But there's a lot of other stuff to study, too, so most people aren't actively looking into it.

  • In the meantime, researchers will keep trying to solve this mystery with what they have.

  • And maybe one day, they'll get to name some new elements because of it.

  • Thanks for watching this episode of SciShow Space!

  • If you'd like to learn more about how stars have transformed the universe,

  • you can watch our episode about the very first stars.

  • Because without their influence, you wouldn't be here.

  • [♪ OUTRO]

[♪ INTRO]

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 star astronomy heavy spectrum iron plutonium

This Star Might Be Hiding Undiscovered Elements | Przybylski’s Star

  • 0 0
    林宜悉 posted on 2020/04/15
Video vocabulary