Anaemic star carries the mark of the ancient ancestor

Australian-led astronomers find probably the most iron-poor star in the Galaxy, hinting at the nature of the first stars in the Universe.

A newly discovered ancient star containing a record-low amount of iron carries proof of a class of even older stars, long hypothesised but assumed to have vanished.

In a paper published within the journal Monthly Notices for the Royal Astronomical Society: Letters, researchers led by Dr Thomas Nordlander of the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) confirm the presence of an ultra-metal-poor red giant star, located in the halo associated with Milky Way, on the other hand regarding the Galaxy about 35,000 light-years from Earth.

Dr Nordlander, through the Australian National University (ANU) node of ASTRO 3D, together with colleagues from Australia, the usa and Europe, located the star with the university’s dedicated SkyMapper Telescope in the Siding Spring s Observatory in NSW.

Spectroscopic analysis indicated that the star had an iron content of only one part per 50 billion.

“That’s like one drop of water in an Olympic swimming pool,” explains Dr Nordlander.

“This incredibly anaemic star, which likely formed just a couple of hundred million years after the Big Bang, has iron levels 1.5 million times less than that of the Sun.”

The very first stars in the Universe are thought to own consisted of only hydrogen and helium, along side traces of lithium. These elements were created in the immediate aftermath of the Big Bang, while all heavier elements have emerged from the heat and pressure of cataclysmic supernovae – titanic explosions of stars. Stars such as the Sun that are rich in heavy element therefore contain material from many generations of stars exploding as supernovae.

As none of this first stars have yet been found, their properties remain hypothetical. These were long anticipated to have been incredibly massive, perhaps a huge selection of times more massive than the Sun, and also to have exploded in incredibly energetic supernovae known as hypernovae.

Dr Nordlander and colleagues suggest that the star was formed after among the stars that are first. That exploding star is located to own been rather unimpressive, just ten times more massive than the sun’s rays buy essay, and also to have exploded only feebly (by astronomical scales) in order for all of the heavy elements created when you look at the supernova fell back in the neutron that is remnant left behind.

Only a small amount of newly forged iron escaped the remnant’s gravitational pull and went on, together with far larger quantities of lighter elements, to form a fresh star – one of many very first second generation stars, which includes now been discovered.

Co-researcher Professor Martin Asplund, a chief investigator of ASTRO 3D at ANU, said it absolutely was unlikely that any true first stars have survived to the present day.

“The good news is like the one we’ve discovered,” he says that we can study the first stars through their children – the stars that came after them.

The research was conducted in collaboration with researchers from Monash University and also the University of brand new South Wales in Australia, the Massachusetts Institute of Technology and Joint Institute for Nuclear Astrophysics, both in the USA, the Max Planck Institute for Astronomy in Germany, Uppsala University in Sweden, and also the University of Padova in Italy.

The ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) is a $40m Research Centre of Excellence funded by the Australian Research Council (ARC) and six collaborating Australian universities – The Australian National University, The University of Sydney, The University of Melbourne, Swinburne University of Technology, The University of Western Australia and Curtin University.

Extra Information:

About SkyMapper

Using a specially-built, 1.3-meter telescope at Siding Spring Observatory near Coonabarabran, the SkyMapper Southern Sky Survey is producing a high-fidelity digital record of the entire southern sky for Australian astronomers.

SkyMapper’s Southern Sky Survey is led by the Research School of Astronomy and Astrophysics at the Australian National University, in collaboration with seven Australian universities plus the Astronomical that is australian Observatory. The aim of the project is always to create a deep, multi-epoch, multi-colour digital survey of this entire sky that is southern. This will facilitate a broad array of exciting science, including discovering the oldest stars into the Galaxy, finding new dwarf galaxies in orbit all over Milky Way, and measuring the consequences of Dark Energy from the Universe through nearby supernovae.

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