Work by Brian O’Shea, an MSU assistant professor of physics and astronomy, and two colleagues indicates that the universe’s earliest inhabitants, known as Population III stars, were not nearly as massive as originally thought. In addition, they argue that many of these stars actually formed in binary systems, that is, pairs of stars that orbit a common center.
The research will be published in the journal Science, and will appear on the Web site Science Express July 9.
“For a long time the common wisdom was that these Population III stars formed alone,” said O’Shea, who also has an appointment in MSU’s Lyman Briggs College. “Researchers also have believed that these stars were incredibly massive – up to 300 times the size of our own sun. Unfortunately, the observations just didn’t jibe with the simulations we created.”
Another clue was that so-called “metals” – all elements other than hydrogen and helium – that are now found in newer stars don’t necessarily match what was thought to be produced when the very massive first stars died.
Very old Population III stars were made essentially of hydrogen and helium. As the stars aged and exploded as supernovae, other elements were formed and these “metals” began showing up in newer stars.
“What we have here,” said O’Shea, “is a fundamental disconnect between observations and theory, because these really massive stars would have produced a different set of metal abundances than what we see in old stars in our galaxy. If a lot of the Population III stars end up being in binary systems, then overall they would be less massive and so when they inevitably died, the metals they produced would be in much better agreement with what we see observationally.”
O’Shea and his colleagues are theoretical astrophysicists, as opposed to traditional observational astronomers. They use supercomputers and custom-designed software to study the formation of cosmological structures such as galaxies.
What really drove this work, O’Shea said, was the development of faster, more powerful computers.
“All of the earlier simulations suggested that when these stars formed they were single, massive stars,” he said. “But now we have faster computers, and we’re able to work out our models to a higher level of detail. Our new simulations found that when you actually resolve everything it is possible that once the gas was going to make the stars, it was bound together tightly enough to make binary stars.”
O’Shea was one of three authors of the paper. The other two were Matthew Turk and Tom Abel of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University. To access a copy of the paper, go here.
This video is a computer simulation in which two binary stars are forming. At the end of the video, the field of view is about 2,000 astronomical units across (one astronomical unit is the distance between the Earth and sun, or about 93 million miles). Video courtesy of Matthew Turk, Tom Abel and O’Shea.
Michigan State University has been advancing knowledge and transforming lives through innovative teaching, research and outreach for more than 150 years. MSU is known internationally as a major public university with global reach and extraordinary impact. Its 17 degree-granting colleges attract scholars worldwide who are interested in combining education with practical problem solving.
Tom Oswald | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy