Ancient Stars of The Milky Way Reveals Prehistoric

The reason why some of the old stars that become abnormal overflowing with heavy elements, as such, because the supernova explosion that sent the jet into space.

Some of the ‘fossil star’ Milky Way – the oldest stars in our galaxy – contains large amounts of heavy elements such as gold, platinum and uranium. Where it came from was a mystery to researchers since these elements are usually seen also on subsequent generations of stars. The researchers at the Niels Bohr Institute have been studying these ancient stars for several years with ESO in Chile giant telescopes in order to trace the origin of heavy elements, and with their recent observations have suggested how these elements can be formed in history beginning of the Milky Way.

The results were published in the Astrophysical Journal Letters.

Shortly after the Big Bang, the universe is dominated by mysterious dark matter together with the hydrogen and helium. As dark matter and gas is clumped under its own gravity, they form the first stars.

On the inside of a hot star, the hydrogen and helium to melt together and form the first elements heavier such as carbon, nitrogen and oxygen, and after a while the ’short’ (a few hundred million years) all the elements were in place . However, these early stars contain only a thousandth of heavy elements contained in the Sun today.

Each time a massive star dies in a fire and loud explosions known as supernovae, it releases the gas cloud and forming new elements into space, where gas clouds contract and eventually collapse and form stars. In this way, a new generation of stars became richer and richer in heavy elements.

Milky Way as NGC 4594 (in picture), disc-shaped spiral galaxy with 200 billion stars. Above and below the galactic plane there is a halo, which includes an old star that has been around since the infancy of galaxies billions of years ago. In principle they all should contain elements of primitive and a bit heavy as gold, platinum and uranium. New research suggests that the explanation lies in the strong jet of massive star explosions. (Credit: Hubble Telescope)

Fossils of the small galaxies

Because of that, really surprised by the discovery of the stars of the early universe is relatively rich in elements that are very heavy. But they were right there and even inside our galaxy, the Milky Way.

“In the outer parts of the Milky Way there is a ‘fossil stars’ parents of the childhood of our galaxy. Old stars in the halo is located above and below the galactic disc pipihan. In a small percentage of the estimate, about 1-2 percent of primitive stars, you find an abnormal amount of the heaviest elements relative to heavy elements ‘normal’ iron and the other, “said Terese Hansen, an astrophysicist in the Astrophysics research group and Planetary Science at the Niels Bohr Institute, University of Copenhagen.

The research group at the Niels Bohr Institute have been studying these ancient stars with giant ESO telescope in Chile for several years. To get a handle on the origin of the elements of severity, they include the 17 stars of ‘normal’ for four years with the Nordic Optical Telescope at La Palma.

Terese Hansen uses his master’s thesis to analyze the observations. “After working hard on these observations it is very difficult for several years, I suddenly realized that three of the stars that have orbital motion is clear that we can define it, while others did not budge from its place and this is an important clue to explain what kind of mechanisms that have created the elements in these stars, “said Terese Hansen, who calculates velositasnya together researchers from the Niels Bohr Institute and Michigan State University, USA.

Gold coated gas cloud

He explained that there are two theories that could explain an overdose of heavy elements in these early stars. One theory is that these stars are all in close binary star systems, in which one star has exploded as a supernova and companion star has been coated with a thin layer of freshly made, namely platinum, uranium, gold and so on.

Another theory is that the initial supernovae (explosions of giant stars) could have fired heavy elements in the form of a jet into a different direction, so that these elements will be built into a diffuse cloud of gas that can form multiple stars we see today in galactic halo.

“My observations on the movement of the stars indicates that most of the 17 stars rich in heavy elements it is actually single. Only three (20 percent) who are in binary star systems – it’s totally normal, 20 percent of all stars are in binary star systems so the theory about gold-plated neighboring star can not be a general explanation. The reason why some of the old stars that become abnormal overflowing with heavy elements, as such, because the supernova explosion that sent the jet into space. In supernova explosions, heavy elements like gold, platinum and uranium are formed and when the jet crashed into the surrounding gas cloud, they will be overwhelmed with these elements and form stars very rich heavy elements, “says Terese Hansen, a PhD funding by one of Europe’s leading astrophysics research group at the University of Heidelberg.