No one visits the red giant any more.
Tucked away in the Milky Way, some 35,000 light-years from Earth, this star is in the late stages of its existence. Sure, it's puffed up and extremely bright, but it's likely heaving its final hydrogen sigh.
When it does, the star — dubbed SMSS J160540.18–144323.1 — will start burning through its helium stores before retiring into the fabric of space.
But if anyone could tell us a story or two about the universe, it's this very extensively named star.
In fact, the newly discovered star may have been born just a few hundred million years after the universe came into existence some 13.8 billion years ago — making it one of the oldest celestial bodies ever analyzed. An international team of astronomers led by by Thomas Nordlander from the Australian National University described the discovery in the Monthly Notices of the Royal Astronomical Society.
And how do you tell a star's age?
For very old stars, scientists often get a clue from its iron content. Billions of years ago, when the universe was just a baby, there wasn't much of it at all. So when stars exploded — and new stars formed from their remains — they contained very little metal.
The lower the iron levels, the older the star.
And SMSS J160540.18–144323.1 has the least amount of iron of any star ever detected.
"This incredibly anaemic star, which likely formed just a few hundred million years after the Big Bang, has iron levels 1.5 million times lower than that of the Sun," Nordlander explains in a statement. "That's like one drop of water in an Olympic swimming pool."
Even more fascinating, the ancient beacon may bear traces of stars that have long since come and gone. The true elders of the cosmos, those stars likely contained just hydrogen and helium — the lightest elements on the periodic table — and no metals at all. So when those massive original stars died — and they likely had short lives — they didn't go supernova, but experienced an even more incredibly energetic demise dubbed hypernova.
Until now, their existence has been entirely hypothetical. But as a rare second-generation star, SMSS J160540.18–144323.1 may have picked up some of the DNA of its ancestors when it formed. And while the elder stars are likely long gone, they may have passed down their stories, in the form of their elements, to the next generation.
Like a dying red dwarf some 35,000 light-years away.
"The good news is that we can study the first stars through their children," study co-author Martin Asplund notes. "The stars that came after them like the one we've discovered."