Boomerang Nebula: ALMA Telescope Discerns Dust From 5,000 Light Years Away, Explaining Star’s Shape
Super telescope in Chile reveals that a dying star has been misunderstood all these years.
Tremendously powerful telescopes able to discern millimeter-sized dust grains surrounding a star 5,000 light years away have lifted the veil off of a dying star to reveal it's been misunderstood.
An international array of telescopes assembled 16,500-foot high ft. high in the Chilean Atacama Desert have recently determined that dust surrounding the middle of the Boomerang Nebula, located in the constellation Centaurus, created an illusory bent middle. Nebula are stars reaching the ends of their lives that have shed their outer gaseous layers. In the case of the Boomerang Nebula, the dust grains created a veil shading much of the central star. The massive telescopes, which astronomers can rearrange at will, helped them discern the dense swath of dust.
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When first observed with ground-based telescopes, this nebula appeared lopsided. Later observations in 2003 with the Hubble Space Telescope mistakenly took the swath of dust to be a bend in the middle of the nebula. But the radio wave telescopes which comprise Atacama Large Millimeter/submillimeter Array (ALMA) are tuned to high frequency radio waves, called millimeter and sub-millimeter wave-energy, radiated by most objects. ALMA is able to detect such energy, even when radiated from the mind-boggling far reaches of the universe.
Water vapor scatters these millimeter and sub-millimeter waves, so the arid climate of the desert site is well-suited for the ALMA arrays of 66 high-precision dish antennas, most of which are 12 meters across.
The new analysis also indicated that the Boomerang Nebula's outer fringes are warming up slightly from its one degree Kelvin — minus 458 degrees Fahrenheit to you and me. The Boomerang Nebula is the coldest known object in the universe — even colder than the afterglow of the Big Bang, which accounts for the natural background temperature of space. The nebula's gas outflow expands and cools similar to how refrigerators employ expanding gas to produce cold temperatures. Astronomers took the nebula's temperature by seeing how it absorbed the cosmic microwave background radiation, which has a consistent temperature of 2.8 degrees Kelvin (minus 455 degrees Fahrenheit).
"This ultra-cold object is extremely intriguing and we're learning much more about its true nature with ALMA," said Raghvendra Sahai, a researcher and principal scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of a paper published about the nebula in the Astrophysical Journal. "Many planetary nebulae have this same double-lobe appearance, which is the result of streams of high-speed gas being jettisoned from the star. The jets then excavate holes in a surrounding cloud of gas that was ejected by the star even earlier in its lifetime as a red giant."
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