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- A tiny speck of star dust took a look at the primitive universe.
- Computer simulations show that a single neutron star collision is an important source of heavy metals.
- Gold is more than bling – it's in our neurons.
If you have a soft spot for gold, you'd better have some money. Not only is the precious metal beautiful, but its quantity in the universe is over. A new study concludes that a simple fusion of neutron stars to some 300 parsecs has produced a significant amount. "This means that in all of us, we would find a value of eyelashes of these elements, mainly in the form of iodine, which is essential to life," said one of the astronomers involved in the study, Imre Bartos of the University of Florida.
Gold in particular is a fascinating subject – it can even be said that our individual lives depend on it, as astronomer Michelle Thaller explains.
"There is gold in your brain."
What it takes to make gold
As Thaller notes, elements such as gold, platinum, plutonium and others have denser atoms and therefore heavier than iron atoms. Gold, in particular, is about four times heavier, with each atom containing many more protons and neutrons than iron. These "heavy" elements are mainly the product of "fast neutron capture" or "r-process". It takes place in conditions of high neutron and heat density – think of violent stellar explosions – that allow a radioactive atomic nucleus to attract free neutrons for an abnormally long interval before its radioactivity begins to occur. disintegrate.
This has been agreed for a while. Until now, however, there had been a debate about the type of cosmic cataclysm responsible: supernovae or neutron star fusions? And how many of these explosive events would be needed to produce the known amount of heavy elements in the universe?
A little bit of star dust tells the story
The finding of the researchers is based on the composition of a single grain of star dust extracted from an Antarctic meteorite by researchers from the University of Arizona, described last month in an article on the astronomy of nature. A cross section of electron-transparent LAP-149 grain – of a size of 1/25000 inch – was examined to determine its composition.
Principal author of the study of analysis, Pierre Haenecour tells News from the AU"As real dust from stars, such presolar grains give us insight into the constituent elements from which our solar system has formed." The composition of LAP-149 suggests formation in nova. Haenecour explains that the most telling clue is that it is extremely enriched in carbon isotope called 13C: "The isotopic composition of carbon from everything we sampled and from any planet or body of our solar system usually varies by a factor of the order of 50 The 13C that we found in the LAP-149 is enriched more than 50,000 times. "
Tom Zega of UA said: "If we could date these objects someday, we could get a better idea of what our galaxy looked like in our region and what triggered the formation of the solar system." In the meantime, he notes: "It is remarkable when one thinks of all the means that should have killed this grain," especially during the violent creation of our solar system.
Image source: UA News
Do the math
Using the traces found in LAP-149, astrophysicists Bartos and Szabolcs Márka of Columbia University conducted a series of computer simulations to determine if they could identify the appropriate circumstances – with both supernovae and neutron star collisions – likely to produce heavier consequences. elements.
They discovered that a simple fusion of two neutron stars could do the trick if it happened about 1000 light-years away from the dust and debris that eventually fused into our solar system, and if that happened about 100 million years before the solar system, or about 4.6 billions of years ago.
Source of image: NASA
From our explosive beginnings
Zega is struck by the implications of LAP-149: "Maybe we owe our existence to a nearby supernova explosion, squeezing clouds of gas and dust with its shockwave, lighting stars and creating starry nurseries, similar to those we see in the famous 'Hubble Pillars of Creation' & # 39; photo.
As for the team that discovered the cataclysm from which so much gold comes, Márka notes: "Our results respond to a fundamental quest of humanity: where do we come from and where are we going? very difficult to describe the vivid emotions that we felt when we realized what we had found and what it meant for the future, while we were looking for an explanation of our place in the universe. "
Hubble goes into high definition to revisit the iconic "pillars of creation". Image Source: NASA, ESA and the Hubble Heritage Team (STScI / AURA)
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