Oldest and Closest White Dwarfs

Scientists from the University of Oklahoma have identified two white dwarf stars considered

the oldest and closest known to man. Astronomers identified these 11- to 12-billion-year-old white dwarfs stars only 100 light-years away from Earth. According to scientists these stars are the closest known examples of the oldest stars in the universe forming soon after the Big Bang. Mukremin Kilic, assistant professor of physics and astronomy in the OU College of Arts and Sciences and lead author on a recently published paper said that a white dwarfs are like a hot stove, once the stove is off, it cools slowly over time. By measuring how cool the stove is, they can tell how long it has been off. The two stars they identified have been cooling for billions of years. Kilic explains that white dwarf stars are the burned out cores of stars similar to the Sun. In about 5 billion years, the Sun also will burn out and turn into a white dwarfs star. It will lose its outer layers as it dies and turn into an incredibly dense star the size of Earth. Known as WD 0346+246 and SDSS J110217, 48+411315.4 (J1102), these stars are located in the constellations Taurus and Ursa Major, respectively. Kilic and colleagues obtained infrared images using NASA’s Spitzer Space Telescope to measure the temperature of the stars. And, over a three-year period, they measured J1102’s distance by tracking its motion using the MDM Observatory’s 2.4-meter telescope near Tucson, Arizona. As said scientists most stars stay almost perfectly fixed in the sky, but J1102 is moving at a speed of 600,000 miles per hour and is a little more than 100 light-years from Earth.
source:www.spacedaily.com

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