Research sheds light on early star formation

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.

Media Contact

Tom Oswald EurekAlert!

More Information:

http://www.msu.edu

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors