A dead star's dusty ring.In 5 billion years, the Years, The the seven decades of Eleanor Pargiter’s life. [Br. Lit.: Benét, 1109] See : Time sun will swell into a huge ball that will fry Earth or even swallow it up. Our star's outer layers will then fly off, and its core will shrink into a dense, fading object 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 . Then what? New images of a dead star are giving scientists a glimpse of what might happen to our solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. when its time comes. [ILLUSTRATION OMITTED] The observations come from the Spitzer Space Telescope Spitzer Space Telescope: see infrared astronomy; observatory, orbiting. , which recently focused on a huge, eye-shaped cloud of gas and dust called the Helix nebula
The Helix Nebula (also known as NGC 7293 , 700 light-years from Earth. The Helix nebula contains the leftover debris that a star spewed as it collapsed. Inside lies a white dwarf that is still hot. This means that the star died only recently. At first, scientists were puzzled by Spitzer's infrared images of the Helix nebula. When the star's outer layers flew off, the researchers expected any extra dust to get pushed away, too. Instead, the images showed lots of dust hovering around the white dwarf, between 35 and 150 astronomical units (AU) away. One AU is the distance between the sun and Earth. In our solar system, many comets orbit the sun within a region called the Kuiper belt Kuiper belt: see comet; Kuiper, Gerard Peter. Kuiper belt or Edgeworth-Kuiper belt Disk-shaped belt of billions of small icy bodies orbiting the Sun beyond the orbit of Neptune, mostly at distances 30–50 times Earth's distance , beyond Neptune. Helix's star might have had orbiting comets, too. The scientists propose that, when the star went poof, its comets started to collide and crumble, creating the distant dust ring. Previously, astronomers had found dusty rings around even older white dwarfs whose nebulae were long gone. Spitzer studies of one of these old stars found that the dust was made up of the same stuff as a typical comet. Other studies have turned up 40 white dwarfs with atmospheres that contain unexpectedly high levels of certain metals, including sodium. So, scientists suspect that these white dwarfs captured the remains of ancient planets, which originally contained the metals. "We're starting to think [that the metals] are probably the smile on the crocodile," says Marc J. Kuchner of NASA's Goddard Space Flight Center The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately 6.5 miles northeast of Washington, D.C. in Greenbelt, Md., "the last bits remaining of a dead planetary system, fed to the white dwarf."--E. Sohn |
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