At noon, Tuesday (Nov. 15), Los Alamos National Laboratory technical staff member Joyce Guzik will talk about some recent research into the nature of the sun's composition and interior during a talk at the Bradbury Science Museum. The talk, "Solar Element Abundances and Helioseismology," is free and open to the public. It is co-sponsored with the museum by the Los Alamos Women in Science organization.
According to Guzik, computer models of the evolution of the sun over the 4.54 billion years since its formation could predict acoustic frequencies caused by these vibrations to within a few tenths of a percent. However, in 2004 the sun's spectrum was re-analyzed using improved atmosphere models and atomic physics. Surprisingly, it was found that the oxygen, carbon and nitrogen abundances in the sun are 30 to nearly 40 percent lower than previously thought, and the abundances of other elements are lower by 10 to 15 percent. The percentage of elements heavier than hydrogen and helium in the sun is now only 1.3 percent instead of the 2 percent previously believed. Now, computer models no longer agree with the helioseismic data, she said. The new abundances of elements don't alter the data on how the sun is vibrating, Guzik explained, but suggest additional research is needed.
In the talk, Guzik will discuss how we know this information and the possibilities being considered to bring the models into agreement again with the acoustic mode data.
"These changes [in the abundance of the sun's elements] may have important effects on ourunderstanding of all of stellar evolution and how the elements in the universe were produced in generations of stars of different masses," Guzik said.
Guzik is a scientist in Los Alamos' Thermonuclear Applications Group. She has been a technical staff member at Los Alamos since 1988 and has a doctoral degree in astrophysics from Iowa State University and bachelor's degrees in physics, math and Russian studies from Cornell College (Iowa).
Guzik conducts astrophysics research at Los Alamos, modeling the interiors and pulsation of the sun and other variable stars, working with many collaborators and students. This summer, Guzik presented her work on the impact of the revised solar abundances at an international stellar evolution and pulsation conference in Rome, Italy, and published this work in the Astrophysical Journal.
The Bradbury Science Museum is located at 15th Street and Central Avenue in downtown Los Alamos. Museum hours apart from special events are 10 a.m. to 5 p.m., Tuesday through Saturday and 1 to 5 p.m., Sunday and Monday. The museum is closed only on Thanksgiving, Christmas and New Year's days.
The museum will be open on Friday, Nov. 11, Veterans Day.
The Bradbury Science Museum is part of Los Alamos' Public Affairs Office.
For more information, contact Pat Berger at 665-0896.
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Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.