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05-19-2024, 12:16 AM
MIT Researchers have reported locating three stars circling our galaxy... buzzing around the galaxy's halo... in the wrong direction.
Also, these three stars appear to be 12 or 13 billion years old. Far too old to have been born in our much younger galaxy.
There has been a suggestion that they must have been 'accreted' into orbit when a smaller globular galaxy was 'absorbed' in the distant past.
Details from MIT News: MIT researchers discover the universe’s oldest stars in our own galactic backyard
Subtitled: Three stars circling the Milky Way’s halo formed 12 to 13 billion years ago.
![[Image: MIT-Oldest-Stars-01-press.jpg?itok=_-SbY-DR]](https://news.mit.edu/sites/default/files/styles/news_article__download/public/download/202405/MIT-Oldest-Stars-01-press.jpg?itok=_-SbY-DR)
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The stars’ low chemical abundance did hint that they originally formed 12 to 13 billion years ago. In fact, their low chemical signatures were similar to what astronomers had previously measured for some ancient, ultrafaint dwarf galaxies. Did the team’s stars originate in similar galaxies? And how did they come to be in the Milky Way?
On a hunch, the scientists checked out the stars’ orbital patterns and how they move across the sky. The three stars are in different locations throughout the Milky Way’s halo and are estimated to be about 30,000 light years from Earth. (For reference, the disk of the Milky Way spans 100,000 light years across.)
As they retraced each star’s motion about the galactic center using observations from the Gaia astrometric satellite, the team noticed a curious thing: Relative to most of the stars in the main disk, which move like cars on a racetrack, all three stars seemed to be going the wrong way. In astronomy, this is known as “retrograde motion” and is a tipoff that an object was once “accreted,” or drawn in from elsewhere.
“The only way you can have stars going the wrong way from the rest of the gang is if you threw them in the wrong way,” Frebel says.
So we have here, in our galactic neighborhood, some stars that were formed at the 'beginning' of our universe. I hope this might be the beginning of our sifting through the 400 billion or so stars remaining... and figuring out a better picture of just how the observable universe has taken its shape, as it were.
Also, these three stars appear to be 12 or 13 billion years old. Far too old to have been born in our much younger galaxy.
There has been a suggestion that they must have been 'accreted' into orbit when a smaller globular galaxy was 'absorbed' in the distant past.
Details from MIT News: MIT researchers discover the universe’s oldest stars in our own galactic backyard
Subtitled: Three stars circling the Milky Way’s halo formed 12 to 13 billion years ago.
...
The stars’ low chemical abundance did hint that they originally formed 12 to 13 billion years ago. In fact, their low chemical signatures were similar to what astronomers had previously measured for some ancient, ultrafaint dwarf galaxies. Did the team’s stars originate in similar galaxies? And how did they come to be in the Milky Way?
On a hunch, the scientists checked out the stars’ orbital patterns and how they move across the sky. The three stars are in different locations throughout the Milky Way’s halo and are estimated to be about 30,000 light years from Earth. (For reference, the disk of the Milky Way spans 100,000 light years across.)
As they retraced each star’s motion about the galactic center using observations from the Gaia astrometric satellite, the team noticed a curious thing: Relative to most of the stars in the main disk, which move like cars on a racetrack, all three stars seemed to be going the wrong way. In astronomy, this is known as “retrograde motion” and is a tipoff that an object was once “accreted,” or drawn in from elsewhere.
“The only way you can have stars going the wrong way from the rest of the gang is if you threw them in the wrong way,” Frebel says.
So we have here, in our galactic neighborhood, some stars that were formed at the 'beginning' of our universe. I hope this might be the beginning of our sifting through the 400 billion or so stars remaining... and figuring out a better picture of just how the observable universe has taken its shape, as it were.
