Oldest Known Star in the Universe

Astronomers have probably found the oldest star of the universe, i.e. nearly 13.2 billion years old, and interestingly it is located near to our Solar System.

“We believe this star is the oldest known in the Universe with a well determined age,” Howard Bond, an astronomer at Pennsylvania State University in University Park, who presented the finding on 10^th of January at a meeting of the American Astronomical Society in Long Beach, California, said in a statement.

This proposed oldest star is referred to as HD 140283 and is located at a distance of approximately 190 light years from us. It is known by the astronomers for more than a century. Researchers already knew that the object is almost entirely made up of hydrogen and helium showing that the star was from the early universe but the exact age of the star was not known.

(Artist’s rendering - HD 140283 – approximately 190 light years from Earth)

Bond and the team members, firstly, determine the more accurate distance of the star from the Solar System with the help of 11 sets of observations recorded between 2003 and 2011 using the Hubble Space Telescope’s Fine Guidance Sensors. They then determine the brightness of the star and calculate its intrinsic brightness as the stars’ dimming brightness is always a very good indicator of their age.

Astronomers found that the star is in such phase of its life cycle in which it is draining the hydrogen at its core. They calculated the age of the star to be 13.9 ± 0.7 billion years old. Consider that this age, in the minus side i.e. 13.2 billion years, is not conflicting with the age of the universe i.e. 13.77 billion years.

The age of this star is known with more confidence than the previously known oldest star, HE 1523-0901, said Bond. HE 1523-0901 is also present in our Milky Way galaxy.

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Source: Cowen, R. (2013). Nearby star is almost as old as the Universe Nature DOI: 10.1038/nature.2013.12196