A group of space detectives, aka astronomers, took another look at three super ancient stars that hang out in the outskirts of our Milky Way galaxy. These stars are so old, they could practically be the grandparents of the universe! The scientists think these stars might not be from around here originally – they might’ve been snatched from other galaxies way back in the cosmic past.
In this cool study published in a fancy journal called Monthly Notices of the Royal Astronomical Society on May 14, these star sleuths reexamined three stars that are about 30,000 light-years away from Earth. Now, that’s pretty far! These stars chill in what’s known as the Milky Way’s “halo,” which is like a big, scattered cloud of stars that hangs out beyond the main part of our galaxy.
Now, get this – these stars are super old, like 12 to 13 billion years old! That’s almost as old as the universe itself, which is mind-blowing. Imagine these stars have been around since basically forever! And get this – these old-timers might not even be from our galaxy originally. They might’ve been swiped from other galaxies during some intense galactic tug-of-wars billions of years ago.
The scientists call these stars “Small Accreted Stellar System” stars, or SASS stars for short. It’s like they’re the ancient relics of the universe, part of our cosmic family tree, as one of the big shot scientists, Anna Frebel from MIT, put it. It’s like finding out your family has ties to ancient royalty or something!
Usually, when scientists want to study really old stars like these, they have to squint at distant galaxies or try to piece together clues from younger stars. But now, it’s like these ancient stars are right in our backyard, giving scientists a front-row seat to study them up close.
So, how did these stars end up in our neck of the cosmic woods? Well, it’s like they hitched a ride on our galaxy as it cruised through space, probably picking up these stars like cosmic hitchhikers during its travels. Imagine the Milky Way as this intergalactic thief, grabbing stars from other galaxies as it moves along!
Now, let’s talk about how these star detectives cracked the case. It all started with a class at MIT taught by Professor Anna Frebel. Imagine being in that class – studying stars and unraveling cosmic mysteries, sign me up! These students dove into data collected by Frebel using some fancy telescopes in Chile.
They found something weird about these stars – they were lacking in heavy metals like iron, strontium, and barium. Now, when we say heavy metals, we’re not talking about the headbanger music kind – we’re talking about elements that are forged inside stars over billions of years. These elements are like the building blocks of the universe, and younger stars usually have plenty of them in their atmospheres.
But these old-timer stars? They were like, “Nah, we’re keeping it light on the heavy metals.” They had way less of them compared to younger stars. It’s like they’re from a time before heavy metal was cool – literally!
So, this got the scientists thinking – maybe these stars didn’t originate in the Milky Way. Maybe they came from somewhere else, like a cosmic immigrant family settling down in a new galactic neighborhood.
To confirm their suspicions, the star sleuths looked at the way these stars were moving through space – their orbital trajectories, if you want to get fancy. And guess what? These stars were rebels – they were moving in the opposite direction from most other stars in our galaxy. It’s like they’re doing the galactic equivalent of driving the wrong way on a one-way street!
Putting all these clues together, the scientists pieced together a pretty compelling story – these stars were probably stolen from other galaxies way back when the universe was still a cosmic toddler. They hitched a ride on the Milky Way and have been cruising around ever since, like celestial nomads.
And you know what’s even cooler? These stars are just the tip of the cosmic iceberg. Scientists think there are more ancient stars out there, waiting to be discovered. It’s like a treasure hunt in the vastness of space!
So, what’s next for these star detectives? Well, they’re probably going to keep scanning the skies, looking for more ancient relics like these stars. Who knows what other cosmic secrets are waiting to be uncovered out there? It’s like the ultimate cosmic mystery – and we’re just getting started!
