The Oldest Star in the Universe
Oldest star is a mystery to scientists for several years. Oldest star known so far is HE 1523-0901. HE 1523-0901 is the name given to a red giant star in the Milky Way galaxy is located approximately seven and a half light-millennia from Earth. This oldest star in the southern part (15:23-0901) of Constellation Libra, Scales of Justice – south of northern Gamma Mu Serpentis and Librae. Due to great distances from Earth, HE 1523-0901 cannot be seen with the naked eye, although this oldest star shines so bright.
It is considered a second-generation Population II, or metal-poor stars ([Fe / H] = -2.95). Oldest star was found in a sample of bright metal-poor halo stars from the Hamburg / ESO Survey by Anna Frebel and collaborators.
Oldest age of this star is measured with ESO telescope is 13.2 billion years old. This makes this oldest star almost as old as estimated age of the universe itself (13.7 billion years as measured by WMAP). It is the oldest old star is determined by the decay of radioactive elements uranium and thorium together with measurements of neutron capture elements of several.
A halo field stars, HE 1523-0901 seems even older than ancient stars in globular clusters are found. This is oldest star in the universe. Very rare in elements heavier than hydrogen and helium (“metals”), HE 1523-0901 was discovered as part of the search for metal-poor halo stars in the survey Hamburg / ESO, which makes it oldest star.