Newly discovered star may not even exist

A star with mass less than the Sun (0.8 or less) that has been discovered in the Milky Way has baffled scientists, who were not expecting there might be something, something that goes against current theories of formation stellar.

The rarity of the star, called SDSS J102915 +172927, is made ​​up almost entirely of hydrogen and helium, with trace amounts of some other element heavier than those two.

A generally accepted theory predicts that stars like this, with low mass and extremely low amounts of metals, should not exist because the clouds of matter from which stars are formed would never condense, "said Elisabetta Caffau leading the author of the discovery team said in a statement from the European Southern Observtorio (ESO ), with whose telescopes in Chile have discovered this rarity.

It was a surprise finding, first, a star in the prohibited area of the theory and means that may have to review the models of star formation, "adds the researcher of University of Heidelberg , Germany, and the Paris Observatory.

SDSS J102915 +172927 (the number syndicate its position in the sky in the constellation Leo) is probably about 13.00 million years, that is formed when the universe (which now has 13,700 million years) was very young. With detectors VLT telescope array, Caffau and his colleagues have found that the proportion of metals in the star is 20,000 times less than that of the Sun.

The hydrogen and helium, plus some bits of lithium, were created shortly after the initial Big Bang, and these light elements would form the first stars. Heavier elements (like carbon, iron, oxygen, etc.) would occur within those stars that explode in the form of supernovae, dispersed in the interstellar medium and the clouds that form in that environment and incorporate new stars collapsed as metals of the stars of the previous generation.

Therefore, the low abundance of light elements in a star is an indicator that is old while the youngest, the proportion of metals by astronomers would be high. SDSS J102915 +172927 is the metal-poor as to be very primitive, it might even be one of the oldest known, explains astronomer Lorenzo Monaco, the ESO. A small star, as this only could have been formed from a cloud of interstellar gas enriched with elements heavier than hydrogen and helium.

But the surprises do not end here with this star. Being so old, you should have a composition similar to that of the universe shortly after the big bang, but it turns out that the proportion of SDSS J102915 +172927 lily is 50 times lower. Is it a mystery that lithium that formed just after the beginning of the universe is destroyed in this star, "says another team member, Piercardo Bonifacio (Paris Observatory).

Scientists have not stopped with this finding is now presented in the journal Nature, and already have several candidates of stars that may have the same SDSS J102915 +172927 features.