Tuesday, February 21, 2012

Tellurium is a rare Earth element also present in distant stars


Article first published as Tellurium, Rare Earth Element, Observed in Three Ancient Stars on Technorati.


Researchers, including researchers from Massachusetts Institute of Technology (MIT), have found that “tellurium” – a brittle and semiconducting, very rare element on Earth – is present in three stars that are present few thousand years away from Earth and are almost 12 billion years old.
Researchers have used the spectrograph from the Hubble Space Telescope, which enabled the light to be split into spectrum of wavelength. The dips in spectrographic data told about the presence of atoms of the rare Earth element as the atoms absorbed certain wavelengths of starlight and gave rise to dips.
This research has also supported the theory that heavier elements in periodic table originated as a result of nuclear fusion from a rare type of supernova.
"We want to understand the evolution of tellurium — and by extension any other element — from the Big Bang to today," says Anna Frebel, an assistant professor of astrophysics at MIT and a co-author on the paper. "Here on Earth, everything's made from carbon and various other elements, and we want to understand how tellurium on Earth came about."
Researchers have also observed that the ratio of barium and strontium is same in all three stars.
"If you look at the periodic table, tellurium is right in the middle of these elements that are hard for us to measure," Jennifer Johnson, an associate professor of astronomy at Ohio State University said. "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 in this sea of unknown-ness."
This research has been published in Astrophysical Journal Letters.
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