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article imageTellurium - rare earth element - found for first time in stars

By Abigail Prendergast     Feb 21, 2012 in Science
Researchers from various institutions such as MIT have found an element called tellurium on three ancient stars. The element, believed to have been created almost 12 billion years ago, is extremely rare on earth, and may further explain our existence.
Various research institutions, including the Massachusetts Institute of Technology (MIT), have discovered the element tellurium in three ancient stars. According to Technorati, tellurium is found on the earth but is extremely rare; the bodies it was found on are currently several thousand light years away and they are estimated to be almost 12 billion years old.
Researchers were able to find trace amounts of the brittle, semi-conducting element on the stars says Science Daily. The discovery also backs the claim "that tellurium, along with even heavier elements in the periodic table, likely originated from a very rare type of supernova during a rapid process of nuclear fusion."
Nuclear fusion happens when a single nucleus is formed by at least two smaller ones. The result of such a process is a heavier nucleus and the action of releasing or absorbing large amounts of energy often occurs alongside it.
The stars themselves reside within the Milky Way and were observed by researchers via the Hubble Telescope reports Discovery.
"We want to understand the evolution of tellurium -- and by extension any other element -- from the Big Bang to today," said Anna Frebel, one of MIT's assistant professors in astrophysics. "Here on Earth, everything's made from carbon and various other elements, and we want to understand how tellurium on Earth came about."
Right after the Big Bang roughly 13.7 billion years ago, the only elements in existence were hydrogen, helium and to some extent, lithium. Fast forward 300 million years, and the universe cooled down; this resulted in clouds of gas which collapsed under gravity. This allowed elements that were heavier than lithium to emerge within the cores of newly formed stars.
However, the heaviest of them all - carbon, oxygen and iron - have a different creation story: one that can only be explained by the phenomenon that is supernovae or the brutal death of stars.
As Frebel and her team examined the composition of the ancient stars "in the Halo of the MIlky Way" from afar, they noticed "dips" in the ultraviolet end of the light spectrum while observing how tellurium absorbs light. This research not only proved that element exists somewhere in space, but a comparison of tellurium to other heavy elements like barium and strontium suggests that the lower portion of the periodic table came about as a result of a rare type of supernova.
For the past 50 years, scientists have mapped out this rapid process - dubbed the r-process - as a means to "unravel the cosmic history of the elements."
"You can make iron and nickel in any ordinary supernova, anywhere in the universe," said Frebel. "But these heavy elements seem to only be made in specialized supernovas. Adding more elements to the observed elemental patterns will help us understand the astrophysical and environmental conditions needed for this process to operate."
Tellurium, being as hard as it was to find in space, remained a mystery as did its formation process and abundance up until now. More work is required to pick up on other yet-to-be-discovered elements that reside in the Milky Way. Tin is highly difficult to detect, and selenium (similar to tellurium) has not been located at any point in the universe beyond this solar system.
"If you look at the periodic table, tellurium is right in the middle of these elements that are hard for us to measure," said Jennifer Johnson, associate professor of astronomy at Ohio State University. "If we need to understand how (the r-process) works in the universe, we really have to measure this part of the periodic table. It's really cool that they got this element (tellurium) in this sea of unknown-ness."
More about Ancient stars, tellurium, Elements
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