Sun’s Sister Star Identified
20 May 2014


This illustration shows various solar systems, consisting of planets circling other stars
 
Credit: NASA

A team of researchers led by University of Texas astronomer Ivan Ramirez has identified the first “sibling” of the Sun, a star believed to have almost certainly formed from the same cloud of gas and cosmic dust within which our parent star was born, about 4.5 billion years ago. This star is known as HD 162826, and lies 110 light years away from Earth. It is invisible to the unaided eye, but can be viewed with binoculars or a small telescope.

The team arrived at this conclusion by determining the star HD 162826 has the same chemical composition as the Sun, including rare elements such as barium and yttrium, and by determining its orbit and plotting backward its revolutions about the center of our Galaxy, the Milky Way.

Ramirez’ methods will help discover other solar sisters, ultimately leading to an understanding of how and where our Sun was born, and how the solar system became hospitable for life.

HD 162826 is 15% more massive than the Sun, and has a slightly hotter surface temperature than that of the Sun. It has
no known planets, but the possibility remains open for discovering small Earth-like planets around this star.

Ramirez’ team has examined 30 candidate solar siblings, found by several research groups around the world, searching for our Sun’s stellar relatives, but the study yielded only one star, HD 162826.

References
McDonald Observatory Website
Wikipedia

Aymen Mohamed Ibrahem
Senior Astronomy Specialist

In May 2014 astronomers at the University of Texas at Austin announced that HD 162826 is "almost certainly" one of what may be thousands of "siblings" of the Sun, emerging from the same stellar nursery some 4.5 billion years ago. They arrived at this conclusion by determining it has the same chemical composition as the Sun, including rare elements such as barium and yttrium, and by determining its orbit and projecting backward its revolutions about the center of our Galaxy, the Milky Way.

The discovery of the first solar sibling by searching for specific rare chemical elements may make it easier to identify other siblings in the future. However, HD 162826 is probably the nearest solar sibling of this type, because others would have been identified earlier, if they had been nearer to the Sun. It had not been expected that even one sibling would be found at this relatively close distance; the study that identified this star investigated the data of only 100,000 stars, in preparation for data about billions of stars expected from the Gaia Space Telescope in five to ten years.

Gaia is an unmanned space observatory of the European Space Agency (ESA), whose mission targets to produce a 3D space catalog of approximately 1 billion astronomical objects.
 
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