Leibniz Institute for Astrophysics, Potsdam | 2018 Oct 08
With the Pristine survey, an international team is looking for and researching the oldest stars in our Universe. The goal is to learn more about the young Universe right after the Big Bang. In a recent publication, the scientists have reported on the discovery of a particularly metal-poor star: a messenger from the distant past.
When studying the early universe, astronomers have different methods at their disposal: One is to look to very large distances and therefore back in time, to see the first stars and galaxies as they were many billions of years ago. Another option is to examine the oldest surviving stars from our own Galaxy, the Milky Way, and use them to get a glimpse of what the conditions were like in the early Universe. The "Pristine" survey, led by Dr Else Starkenburg from the Leibniz Institute for Astrophysics Potsdam (AIP) and Nicolas Martin from the University of Strasbourg, is looking to do just that.
The scientists employ a special colour filter on the Canada-France-Hawaii Telescope to search for stars with relatively pristine atmospheres. In their recent publication they have used this technique to discover one of the most metal-poor stars known. Detailed follow-up studies with spectrographs of the Isaac Newton Group in Spain and the European Southern Observatory in Chile have demonstrated that the star has indeed very few heavy elements in its atmosphere. "The star contains less than one ten- thousandth of the metal content of the Sun. Additionally, its detailed pattern of different elements stands out. Whereas most metal-poor stars that exhibit such low levels of elements like iron and calcium also show a significant enhancement in carbon, this star does not. This makes it the second star of its kind ever discovered, and an important messenger from the early Universe", says Else Starkenburg. ...
The Pristine Survey IV: Approaching the Galactic Metallicity Floor
with the Discovery of an Ultra-Metal-Poor Star ~ Else Starkenburg et al