Rare stars discovered in original galaxy may answer important questions about the ingredients of life: Space Photo of the Week

This stunning snapshot, taken by the Dark Energy Camera (DECam) mounted atop the Victor M. Blanco 4-meter (13-foot) Telescope in Chile, shows a bright field of stars inside Pictor II, a dwarf galaxy that is more than 10 billion years old.

However, it is not just a beautiful picture. In this image is the star PicII-503. This is a very old stellar reactor, classified as a Population II, or second generation, star, making it one of the oldest stars in the universe.

Population II stars formed when the universe was young and stars had not yet fused heavy elements into existence. This means that the star is composed primarily of hydrogen and helium. This means that PicII-503 contains approximately 1 to 40,000 times less iron than the much younger Sun.

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However, the star’s lack of iron is compensated for by carbon. Like many Pop II stars, PicII-503 is unusually rich in material, with a carbon-to-iron ratio more than 1,500 times that of the Sun, the researchers said in a statement.

Astronomers have proposed many theories as to why this is the case, but these suggestions have been difficult to test because many Pop II stars are discovered after they have emigrated from their birthplace.

But since PicII-503 is still located within a proto-dwarf galaxy, astronomers played the role of “stellar archaeologists” and used the star’s composition to test their theories. The star’s carbon-rich composition lends credence to the idea that the lighter carbon in the star’s outer shell is blown farther than other elements during violent supernova explosions at the end of a star’s life.

This may also explain why carbon is an element so ubiquitous in the universe that it is highly suited to serve as a key building block for life.