If he is right, the heavy atom abundances in the genesis star provide a “window” on the very first stars – short-lived, super-massive stars that blew up and disappeared 13.5 billion years ago. “The star has 10,000 times as much carbon relative to iron as the Sun,” says Beers. “In fact, it has the highest carbon abundance of any known star.”Finding a star with such low levels of most heavy atoms and an enhanced level of carbon is like finding a 120-year-old with skin as soft as six-month-old baby.Beers believes the enhanced carbon reflects atom-building processes going on in the very first stars, whose explosions provided the raw material for the genesis star. “We can therefore say that neutron-capture processes, which made many of the atoms in the periodic table, probably got going some time between 13.5 and 13 billion years ago,” says Beers.Not everything about the genesis star makes sense. “The genesis star must therefore have come from a time before the onset of significant neutron-capture processes, which produce many of the heavier atoms in today’s Universe,” says Beers.By contrast, many ancient stars with 1000 times less iron – estimated to be about 13 billion years older than the Sun – do contain atoms heavier than iron. Atoms heavier than iron are built up by the repeated capture of particles called neutrons, either during the late stages of stars’ lives or during the catastrophic explosions in which massive stars die.

“HE 0107-5240 was truly the genesis star,” says Beers.One of the most significant features of the star’s spectrum is the total lack of any atoms heavier than nickel or iron. According to the best estimates, it was 13.5 billion years old, meaning it was around only 200 million years after the Big Bang. What’s more, it had hardly any heavy atoms – just seven different kinds compared with 25 to 30 in old stars with 1000 times less iron than the Sun It had to be the most ancient star ever found. “What we got stunned us,” says Beers.HE 0107-5240 had 200,000 times less iron than the Sun – 200 times less than any known star. They then looked at promising candidates in detail using some of the world’s largest telescopes “One star jumped out at us,” says Beers. “It went by the rather uninspiring name of HE 0107-5240.”At the end of 2001, Beers and his colleagues spent a mammoth six hours collecting light from the star with the Very Large Telescope on Cerro Paranal in Chile.

In the early 1990s, astronomers from the University of Hamburg and the European Southern Observatory studied 4 million stars across the sky. “The lost generation of stars blew up and vanished around 13 billion years ago,” says Timothy Beers of Michigan State University in East Lansing. “They’re the missing jigsaw piece in cosmic history.”
Astronomers believe the universe’s earliest stars formed in small gas clouds, containing only a few dozen or a few hundred stars. Later, these clusters coalesced to form giant galaxies like the Milky Way which dominate today’s universe.