https://www.sciencealert.com/astron...ing-star-that-s-nearly-as-old-as-the-universe Astronomers Have Found a Record-Breaking Star That's Nearly as Old as The Universe MICHELLE STARR 5 AUG 2019 Another ancient star has been found lurking in the Milky Way. Around 35,000 light-years away, a red giant star named SMSS J160540.18–144323.1 was found to have the lowest iron levels of any star yet analysed in the galaxy. This means that it's one of the oldest stars in the Universe, probably belonging to the second generation of stars after the Universe burst into existence 13.8 billion years ago. "This incredibly anaemic star, which likely formed just a few hundred million years after the Big Bang, has iron levels 1.5 million times lower than that of the Sun," explained astronomer Thomas Nordlander of the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions and the Australian National University. "That's like one drop of water in an Olympic swimming pool." And that's how we can tell how old the star is, because the very early Universe had no metals at all. The first stars were made up primarily of hydrogen and helium, and were thought to be very massive, very hot, and very short-lived. These stars are called Population III, and we've never seen them. more at link..... the paper: https://academic.oup.com/mnrasl/article-abstract/488/1/L109/5533336?redirectedFrom=fulltext The lowest detected stellar Fe abundance: the halo star SMSS J160540.18−144323.1: ABSTRACT: We report the discovery of SMSS J160540.18−144323.1, a new ultra metal-poor halo star discovered with the SkyMapper telescope. We measure [Fe/H]=−6.2±0.2[Fe/H]=−6.2±0.2 (1D LTE), the lowest ever detected abundance of iron in a star. The star is strongly carbon-enhanced, [C/Fe]=3.9±0.2[C/Fe]=3.9±0.2, while other abundances are compatible with an α-enhanced solar-like pattern with [Ca/Fe]=0.4±0.2[Ca/Fe]=0.4±0.2, [Mg/Fe]=0.6±0.2[Mg/Fe]=0.6±0.2, [Ti/Fe]=0.8±0.2[Ti/Fe]=0.8±0.2, and no significant s- or r-process enrichment, [Sr/Fe]<0.2[Sr/Fe]<0.2 and [Ba/Fe]<1.0[Ba/Fe]<1.0 (3σ limits). Population III stars exploding as fallback supernovae may explain both the strong carbon enhancement and the apparent lack of enhancement of odd-Z and neutron-capture element abundances. Grids of supernova models computed for metal-free progenitor stars yield good matches for stars of about 10M⊙10M⊙ imparting a low kinetic energy on the supernova ejecta, while models for stars more massive than roughly 20M⊙20M⊙ are incompatible with the observed abundance pattern.
Another supposed candidate for the oldest star is the Methuselah Star once predicted to be 14.5 billion years old. More potential excitement for the media! Obviously no star is older then the BB and the universe. The BB of course has itsef been subject to increasing precisions as to how far back it occurred. When I was as kid it was 15 billion years...that has been refined somewhat to 13.83 billion years. The error range with regards to distance and age and methodologies used in measuring distances of stars is also open to refinement...... https://www.space.com/20112-oldest-known-star-universe.html Scientists have known about HD 140283 for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about 800,000 mph (1.3 million km/h) and covers the width of thefull moon in the sky every 1,500 years or so, researchers said. The star is just passing through the Earth's neck of the galactic woods and will eventually rocket back out to the Milky Way's halo, a population of ancient stars that surrounds the galaxy's familiar spiral disk. The Methuselah star, which is just now bloating into a red giant, was probably born in a dwarf galaxy that the nascentMilky Way gobbled up more than 12 billion years ago, researchers said. The star's long, looping orbit is likely a residue of that dramatic act of cannibalism. Distance makes the difference Hubble's measurements allowed the astronomers to refine the distance to HD 140283 using the principle of parallax, in which a change in an observers' position — in this case, Hubble's varying position in Earth orbit — translates into a shift in the apparent position of an object. They found that Methuselah lies 190.1 light-years away. With the star's distance known more precisely, the team was able to work out Methuselah's intrinsic brightness, a necessity for determining its age. The scientists also applied current theory to learn more about the Methuselah star's burn rate, composition and internal structure, which also shed light on its likely age. For example, HD 140283 has a relatively high oxygen-to-iron ratio, which brings the star's age down from some of the earlier predictions, researchers said. In the end, the astronomers estimated that HD 140283 was born 14.5 billion years ago, plus or minus 800 million years. Further observations could help bring the Methuselah star's age down even further, making it unequivocally younger than the universe, researchers said. <<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Add that to the fact that the universe's age as I mentioned previously, also has an error range of about 800 million years, and the so called mystery diminishes somewhat. And of course it also would bring Einstein's GR into question, one of the 20th century's greatest models and highly successful. Perhaps as the original article mentions, gravitational waves may bring these margins for errors down further.
A recent article and paper..... https://astronomy.com/news/2018/05/first-stars-from-oxygen The first stars formed when the universe was less than 2% its current age: Astronomers have detected a 13.3-billion-year-old oxygen signal, which suggests the first stars began forming just 250 million years after the Big Bang. more at link.... the paper: https://www.nature.com/articles/s41586-018-0117-z The onset of star formation 250 million years after the Big Bang:
