11-Billion-Year-Old Giant Supernovae Farthest Ever Detected
July 8, 2009
Eta Carinae, a star in the Milky Way galaxy that is 7,500 light years from Earth, will become a supernova similar to those detected by Jeff Cooke and colleagues. In contrast, the newly found supernovae are more than a million times as far away. Image: NASA
(PhysOrg.com) -- UC Irvine cosmologists have found two supernovae farther away than any previously detected by using a new technique that could help find other dying stars at the edge of the universe.
This method has the potential to allow astronomers to study some of the very first supernovae and will advance the understanding of how galaxies form, how they change over time and how Earth came to be.
"When stars explode, they spew matter into space. Eventually, gravity collapses the matter into a new star, which could have planets such as Earth around it," said Jeff Cooke, McCue Postdoctoral Fellow in physics & astronomy, who reports his findings July 9 in the journal Nature.
The supernovae Cooke and colleagues found occurred 11 billion years ago. The next-farthest large supernova known occurred about 6 billion years ago.
A supernova occurs when a massive star (more than eight times the mass of the sun) dies in a powerful, bright explosion. Cooke studies larger stars (50 to 100 times the mass of the sun) that blow part of their mass into their surroundings before they die. When they finally explode, the nearby matter glows brightly for years.
Typically, cosmologists find supernovae by comparing pictures taken at different times of the same swath of sky and looking for changes. Any new light could indicate a supernova.
Cooke built upon this idea. He blended pictures taken over the course of a year, then compared them with image compilations from other years.
"If you stack all of those images into one big pile, then you can reach deeper and see fainter objects," Cooke said. "It's like in photography when you open the shutter for a long time. You'll collect more light with a longer exposure."
Doing this with images from the Canada-France-Hawaii Telescope in Hawaii, Cooke found four objects that appeared to be supernovae. He used a Keck telescope to look more closely at the spectrum of light each object emitted and confirmed they were indeed supernovae.
"The universe is about 13.7 billion years old, so really we are seeing some of the first stars ever formed," Cooke said.
Cooke and other scientists with UCI's Center for Cosmology last year discovered a cluster of galaxies in a very early stage of formation that occurred 11.4 billion years ago, the farthest of its kind ever detected. The galaxy proto-cluster, named LBG-2377, is giving cosmologists unprecedented insight into galaxy formation and the evolution of the universe.
Source: University of California - Irvine
Mar 31, 2008 |
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"When stars explode, they spew matter into space. Eventually, gravity collapses the matter into a new star, which could have planets such as Earth around it"
Right. About three decades ago measurements first showed that the Earth and the Sun formed in this manner ["Elemental and isotopic inhomogeneities in noble gases: The case for local synthesis of the chemical elements", Trans. Missouri Academy of Science 9 (1975) 104-122; "Strange xenon, extinct super-heavy elements and the solar neutrino puzzle", Science 195 (1977) 208-209; "Isotopes of tellurium, xenon and krypton in the Allende meteorite retain record of nucleosynthesis", Nature 277 (1979) 615-620; Noble gas anomalies and synthesis of the chemical elements", Meteoritics 15 (1980) 117-138; "Heterogeneity of isotopic and elemental compositions in meteorites: Evidence of local synthesis of the elements ", Geokhimiya No. 12 (1981) 1776-1801].
Measurements which have since confirmed this supernova birth of the solar system are summarized here: "Composition of the solar interior: Information from isotope ratios", Proceedings of SOHO/GONG Conference on Helioseismology, 27 Oct-1 Nov 2002, Big Bear Lake, CA, U.S.A. (ESA SP-517, editor: Huguette Lacoste, 2003) 345-348 ISBN: 92-9092-827-1
http://arxiv.org/...410717v1
NASA's Spitzer Space Telescope observed in 2006 that onion-like layers of elements in a supernova remain unmixed after the explosion.
See NASA Report of October 26, 2006: "Once an Onion, Always an Onion"
http://tinyurl.com/3xoltt
With kind regards,
Oliver K. Manuel
http://www.omatumr.com