From Ohio U: “Probing Red Giants with a DRAGON”

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Ohio University

June 9, 2016
Jean Andrews

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Scientists study stars called red giants to better understand processes such as nuclear fusion—the dominant source of energy for stars in the universe. L to R: Dr. Carl Brune, Dr. Annika Lennarz, a TRIUMF postdoctoral researcher, OHIO doctoral students Som Nath Paneru, and Rikam Giri

Dr. Carl Brune, Professor of Physics & Astronomy and member of the Institute of Nuclear and Particle Physics (INPP), traveled recently to TRIUMF, Canada’s national lab for nuclear and particle physics, located in Vancouver. With him were his doctoral students Rekam Giri and Som Nath Paneru. The purpose of their visit was to use the DRAGON, a specialized instrument which measures the fusion of helium and carbon — an important process that occurs in red giant stars.

DRAGON at TRIUMF

“These measurements will help us to understand where the oxygen in the universe comes from and help to confirm that our models for how stars evolve and produce elements are correct, “ Brune says. “The DRAGON is an ideal instrument for this type of experiment.”

The DRAGON apparatus is used to study nuclear reactions important in astrophysics. By recreating the nuclear reactions that occur inside exploding stars, researchers are better able to understand reactions that produce the chemical elements and energy generation in stars. DRAGON is an acronym for Detector of Recoils And Gammas Of Nuclear reactions.

How Stars Evolve into Red Giants

Brune is particularly interested in energy processes taking place within red giants. These are stars in the last stages of stellar evolution that have exhausted the supply of hydrogen in their cores and have begun thermonuclear fusion of hydrogen in a shell surrounding the core.

“Most stars, including our sun, are burning hydrogen in the cores,” Brune explains. “Once the hydrogen in the core is exhausted, the stars begin to burn helium and become red giants. They expand in diameter and their outer edge is lower in temperature, giving them a reddish-orange hue. Helium is burned by two fusion reactions within a red giant: the fusion of three helium nuclei into carbon and the fusion of helium with carbon to form oxygen.”

The fusion of helium with carbon at this stage is thought to be the main source of oxygen in the universe – even the oxygen on the earth.

The DRAGON instrument at TRIUMF is a recoil separator that is used to detect the oxygen nuclei produced. A carbon beam was used to bombard a helium target. The oxygen nuclei produced by fusion are separated from the carbon beam by the DRAGON instrument and counted.

Brune, Giri, and Paneru are part of a team of nuclear physicists that includes researchers from TRIUMF, the Colorado School of Mines, and Michigan State University. The group convened the week of May 3-10 to run the experiment using the DRAGON.

See the full article here .

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n 1786, 11 men gathered at the Bunch of Grapes Tavern in Boston to propose development of the area north of the Ohio River and west of the Allegheny Mountains known then as the Ohio Country. Led by Manasseh Cutler and Rufus Putnam, the Ohio Company petitioned Congress to take action on the proposed settlement. The eventual outcome was the enactment of the Northwest Ordinance of 1787, which provided for settlement and government of the territory and stated that “…schools and the means of education shall forever be encouraged.”

In 1803, Ohio became a state and on February 18, 1804, the Ohio General Assembly passed an act establishing “The Ohio University.” The University opened in 1808 with one building, three students, and one professor, Jacob Lindley. One of the first two graduates of the University, Thomas Ewing, later became a United States senator and distinguished himself as cabinet member or advisor to four presidents.

Twenty-four years after its founding, in 1828, Ohio University conferred an A.B. degree on John Newton Templeton, its first black graduate and only the third black man to graduate from a college in the United States. In 1873, Margaret Boyd received her B.A. degree and became the first woman to graduate from the University. Soon after, the institution graduated its first international alumnus, Saki Taro Murayama of Japan, in 1895.