Found the oldest known stars

A team of astronomers of the Australian National University (Australian National University) found a star, which, according to measurements, originated shortly after the Big Bang, about 13.7 billion years ago. The conclusion of this discovery is set out in the work to which the preprint is available. In order not to produce many guesses, that there are words of scientists, and that - the popularization of other scientists and the interpretation of journalists, I cite the translation of the abstract of their work , and then the interpretation of data and conclusions from other articles.

A single low-energy, iron-poor supernova may have been the source of material for the star SMSS J 031300.36-670839.3

The proportions of chemical elements in 4 low-mass stars and their extremely low metallization show that the gas from which they were formed was very little enriched with metals, and probably resulted from a low-energy explosion of a supernova. Such supernovae produce a large proportion of light elements such as carbon and very little iron. The existence of supernovae of this kind is unusual, because it is assumed that the first stars were extremely massive, and when destroyed from an unstable state, galaxies were quickly enriched with iron. The share of iron from the supernova in the spectrum of the star could not be found. The SMSS J031300.36-670839.3 spectrum does not show any signs of iron at all, which [in measurement errors] indicates its proportion to less than 10 ^-7.1 [= 8 * 10 ^-8 ] in comparison with the solar concentration.

[Preview charts from Nature ]
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Based on the fraction of iron from known models, we conclude that the star was created from a material by a supernova with an initial mass of 60 solar masses (and which left a black hole after it), and we conclude that such stars existed in the early Universe, which produced an insignificant iron yield . Reducing the level of metallization allowed spawning the stars of the first generation [in chemical composition] for a long period. We believe that such stars could play an important role in the era of cosmic reionization and chemical evolution of early galaxies.

end of the preprint annotation

There is a paid, unwrapped version of an article in a scientific journal, and there are already articles that help interpret the meanings and meanings of numbers in this discovery to ordinary readers.

Translations and news reports, as you can understand, are full of inaccuracies. For example, in one place it was considered that an open star (and not a supernova that exploded once) has a mass of 60 solar masses, in another they called the order of an iron fraction - less than 10 ^-6 , which, of course, is true, but not precise, in the third they added manganese in the composition of the old star.

We give useful accompanying facts collected by journalists around this event, avoiding inaccuracies.

* The age of the stars was learned to determine not only by their position on the Hertzsprung-Russell diagram, but also by the chemical composition of the spectrum of stars. It was found that the younger the stars and the later they were born from the moment of the Big Bang, the more heavy metals and iron in their atmosphere. This is explained by the fact that the substance of the Universe, which initially consisted of a fairly certain proportion of hydrogen (75%), helium (25%), a small fraction of lithium and beryllium, began to be enriched with thermonuclear fusion products, which occurred in the depths of very massive and therefore unstable stars. They exploded like supernovae and threw synthesis products into space. This process continues to this day. Stars are again condensed from cosmic gas and dust, but this time heavy elements and metals are present in their atmosphere, and not only in the invisible core. Formed the term: "metallicity" of stars. The older the star, the less its metallicity.

* A 5-year program to search for old stars based on their spectra has recently started. The last "victim" (discovery) so far has been the star HD 140283 (13.2 billion years) from the constellation Libra, 190 St. years from Earth, discovered in early 2013. The current open star is estimated at 13.7 billion years, roughly 100–200 million years after the Big Bang. It is located 6,000 light-years from Earth in the constellation of South Hydra . It is possible that the search for this program will bring new discoveries, and undoubtedly more ancient stars will be found in the future.

* arxiv.org/abs/1402.1517 (source submitted on Feb 6 2014)
* SMSS J031300.36−670839.3 ( single , published online 09 February 2014; received 09 July 2013; accepted 05 December 2013) A single low-energy, iron-poor supernova
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