The supernova observed by Johannes Kepler in
1604, known as “Kepler’s supernova,” came from a relatively young star that was
rich in metals, according to research published by The Astrophysical Journal Letters and co-authored by a UT Arlington
A composite image of Kepler’s
supernova from the Chandra X-ray Observatory. (Courtesy of the
Harvard-Smithsonian Center for Astrophysics and NASA)
The new work – recently released online - expands upon what’s already known about Type Ia supernovae—stellar explosions used to calibrate theories about the expansion of our universe.
Scientists have long thought all Type Ia supernovae were much the same with a standard brightness that could be measured and used to calculate distances to galaxies in the universe. But they’ve known less about the progenitor white dwarf stars—those that exploded within a supernova—known as Type Ia supernova.
The study is currently featured on the NASA website at http://www.nasa.gov/mission_pages/astro-e2/news/post-mortem.html.
Sangwook Park, a University of Texas at Arlington assistant professor of physics, Carles Badenes, an assistant professor of physics and astronomy at the University of Pittsburgh, and their collaborators set out to use X-ray observation data from the Japanese/United States Suzaku Observatory to further explore Type Ia progenitors and, more specifically, how they explode. Ultimately, the researchers sought to determine if differences in Type Ia origins could mean they are not as similar as once thought.
The team’s research was selected as a “key project” by the Suzaku Observatory, which gave them added observational time. They used two weeks worth of X-ray spectroscopy observations to examine the remnant of Kepler’s supernova, an unusually powerful explosion in the Milky Way. The emission lines from the ionized gas in the remnant - for iron, chromium, manganese and nickel - are indicative of a very young star, Park said. Metallicity is a measure of chemicals heavier than hydrogen making up a sample.
“Even with all that is known about the universe and its expansion, there are still some systematic uncertainties in the way Type Ia supernovae are used,” Park said. “If we can get a better idea about those uncertainties, it will make a significant contribution to improve the accuracy of the distance measurements for galaxies far away from our own Milky Way Galaxy. It also would likely contribute to the understanding of the acceleration of the universe’s expansion and the role of dark energy.”
In 2011, astrophysicists from the United States and Australia won the Nobel Prize for Physics with their discovery that the universe is expanding at an accelerating rate, in large part due to the presence of a mysterious property called “dark energy.” Today, understanding dark energy has become one of the most sought-after goals in science.
Badenes said knowing more about the variation in stars that produce Type Ia supernovae is unlikely to shake the Nobel Prize winners’ discovery, but it could help pin down the properties of dark energy.
“It’s taking the measurements one step forward,” Badenes said.
Other co-authors on the recently published paper include: Koji Mori and Ryohei Kaida, of the University of Miyazaki (Japan); Eduardo Bravo, of the University Politécnica de Catalunya (Spain); Andrew Schenck, of UT Arlington; Kristoffer A. Eriksen, of Los Alamos National Laboratory; John P. Hughes, of Rutgers University; Patrick O. Slane, of the Harvard-Smithsonian Center for Astrophysics; David N. Burrows, of Pennsylvania State University; and Jae-Joon Lee, of the Korea Astronomy and Space Institute.
The paper is called “A Super-Solar Metallicity for the Progenitor of Kepler’s Supernova.” The team’s work was supported by grants from NASA and the Ministry of Education, Culture, Sports, Science and Technology – Japan, or MEXT.
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