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!
A new kind of quantum bits in two dimensions
19.03.2018 | Vienna University of Technology
'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
19.03.2018 | Physics and Astronomy
19.03.2018 | Materials Sciences
19.03.2018 | Event News