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Washington: Scientists
have detected traces of a rare earth element, tellurium, in three
ancient stars located a few thousand light years away, a study
reveals.
Traces of this brittle, semiconducting element were found with
even heavier elements in the periodic table, for the very first
time, possibly originating from a very rare type of supernova
during rapid nuclear fusion.
"We want to understand the evolution of tellurium -- and by
extension any other element from the Big Bang to today," said
study co-author Anna Frebel, assistant professor of astrophysics
at Massachusetts Institute of Technology (MIT).
"Here on Earth, everything's made from carbon and various other
elements, and we want to understand how tellurium on Earth came
about," the Astrophysical Journal Letters reported.
The team analyzed the chemical composition of three bright stars
located a few thousand light-years away, "in the halo of the Milky
Way," Frebel said, according to a university statement.
Researchers looked at data obtained from the Hubble Space
Telescope's spectrograph, an instrument that splits light from a
star into a spectrum of wavelengths.
If an element is present in a star, the atoms of that element
absorb starlight at specific wavelengths; scientists can observe
this absorption as dips in the spectrograph's data.
Frebel and her colleagues detected dips in the ultraviolet region
of the spectrum -- at a wavelength that matched tellurium's
natural light absorption -- providing evidence that the rare Earth
element does indeed exist in space, and was likely created more
than 12 billion years ago, at the time when all three stars
formed.
The researchers also compared the abundance of tellurium to that
of other heavy elements such as barium and strontium, finding that
the ratio of elements was the same in all three stars.
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