A dead star's ghostly glow27 October 2016, by Ray Villard

Astronomers discovered a real "tell-tale heart" in space,6,500 light-years from Earth. The "heart" is the crushedcore of a long-dead star, called a neutron star, whichexploded as a supernova and is now still beating withrhythmic precision. Evidence of its heartbeat are rapid-fire, lighthouse-like pulses of energy from the fast-spinning neutron star. The stellar relic is embedded inthe center of the Crab Nebula, the expanding, tatteredremains of the doomed star. Credit: NASA and ESA,Acknowledgment: M. Weisskopf (NASA's MarshallSpace Flight Center)

The eerie glow of a dead star, which exploded longago as a supernova, reveals itself in this NASAHubble Space Telescope image of the CrabNebula. But don't be fooled. The ghoulish-lookingobject still has a pulse. Buried at its center is thestar's tell-tale heart, which beats with rhythmicprecision.

The "heart" is the crushed core of the explodedstar. Called a neutron star, it has about the samemass as the sun but is squeezed into an ultra-dense sphere that is only a few miles across and100 billion times stronger than steel. The tinypowerhouse is the bright star-like object near thecenter of the image.

This surviving remnant is a tremendous dynamo,spinning 30 times a second. The wildly whirling

object produces a deadly magnetic field thatgenerates an electrifying 1 trillion volts. Thisenergetic activity unleashes wisp-like waves thatform an expanding ring, most easily seen to theupper right of the pulsar.

The nebula's hot gas glows in radiation across theelectromagnetic spectrum, from radio to X-rays.The Hubble exposures were taken in visible light asblack-and-white exposures. The Advanced Camerafor Surveys made the observations betweenJanuary and September 2012. The green hue hasbeen added to give the image a Halloween theme.

The Crab Nebula is one of the most historic andintensively studied supernova remnants.Observations of the nebula date back to 1054 A.D.,when Chinese astronomers first recorded seeing a"guest star" during the daytime for 23 days. Thestar appeared six times brighter than Venus.Japanese, Arabic, and Native American stargazersalso recorded seeing the mystery star. In 1758,while searching for a comet, French astronomerCharles Messier discovered a hazy nebula near thelocation of the long-vanished supernova. He lateradded the nebula to his celestial catalog as"Messier 1," marking it as a "fake comet." Nearly acentury later British astronomer William Parsonssketched the nebula. Its resemblance to acrustacean led to M1's other name, the CrabNebula. In 1928 astronomer Edwin Hubble firstproposed associating the Crab Nebula to theChinese "guest star" of 1054.

The nebula, bright enough to be visible in amateurtelescopes, is located 6,500 light-years away in theconstellation Taurus.

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This time-lapse movie of the Crab Nebula, made fromNASA Hubble Space Telescope observations, revealswave-like structures expanding outward from the "heart"of an exploded star. The waves look like ripples in apond. The heart is the crushed core of the exploded star,or supernova. Called a neutron star, it has about thesame mass as the sun but is squeezed into an ultra-dense sphere that is only a few miles across and 100billion times stronger than steel. This surviving relic is atremendous dynamo, spinning 30 times a second. Therapidly spinning neutron star is visible in the image as thebright object just below center. The bright object to theleft of the neutron star is a foreground or backgroundstar. The movie is assembled from 10 Hubble exposurestaken between September and November 2005 by theAdvanced Camera for Surveys. Credit: NASA and ESA,Acknowledgment: J. Hester (Arizona State University)

Provided by NASA's Goddard Space Flight CenterAPA citation: A dead star's ghostly glow (2016, October 27) retrieved 27 March 2022 from https://phys.org/news/2016-10-dead-star-ghostly.html

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