Shedding light on the precursor to a supernova.By examining gas lit up by an exploding star, astronomers have obtained new insight into how a common type of supernova erupts. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. a widely accepted model, the stage is set for a type la supernova when a dense, Earthsize star called a white dwarf white dwarf, in astronomy, a type of star that is abnormally faint for its white-hot temperature (see mass-luminosity relation). Typically, a white dwarf star has the mass of the sun and the radius of the earth but does not emit enough light or other radiation to be steals gas from a bloated companion star. When the gas-guzzling white dwarf tips the scales at more than 1.4 times the mass of the sun, it blows to smithereens smith·er·eens pl.n. Informal Fragments or splintered pieces; bits: The fragile dish broke into smithereens. . That's the theory, but astronomers aren't sure that they've got it exactly right. Getting the model correct is critical because researchers rely on type la supernovas to measure the distance and expansion rate of the universe. Ferdinando Patat of the European Southern Observatory European Southern Observatory (ESO), an intergovernmental organization for astronomical research with headquarters in Garching, near Munich, Germany. The ESO began in 1962 as a consortium among Belgium, Denmark, France, Germany, the Netherlands, and Sweden. in Garching, Germany, and his colleagues studied in detail the type la supernova SN 2006X, recorded by telescopes last year as it erupted in a galaxy 70 million light-years from Earth. Spectra taken at the Very Large Telescope The Very Large Telescope Project (VLT) is a system of four separate optical telescopes (the Antu telescope, the Kueyen telescope, the Melipal telescope, and the Yepun telescope) organized in an array formation. Each telescope has an 8.2 m aperture. in Paranal, Chile, and the Keck Observatory on Hawaii's Mauna Kea show evidence of fast-moving clumps of material near the exploded white dwarf. The speed of the clumps, about 50 kilometers per second, and their separation suggest that they were probably expelled by a red giant star--the white dwarf's presumed companion--about 50 years before the dwarf detonated. Red giants are known to have strong winds that could carry off large dumps of material at the measured speeds. By indicating the presence of a red giant, the observations support the prevailing model of how type la supernovas detonate det·o·nate intr. & tr.v. det·o·nat·ed, det·o·nat·ing, det·o·nates To explode or cause to explode. [Latin d , Patat's team reports in an upcoming Science.--R.C. |
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