Printer Friendly

Doing the pulsar twist.

Doing the pulsar twist

This "mystery spot,' the supernova's bright "companion,' also perplexes astronomers because they have a hard time figuring out what could produce it. Stirling Colgate of Los Alamos (N.M.) National Laboratory suggests what might have made the spot, which he calls "son of supernova.' It is part of his explanation of why a supernova explosion doesn't fall back on itself, and it involves the magnetic field of the pulsar that may form inside the supernova.

In 20 years of calculating how supernova explosions occur, Colgate says, he has always been puzzled by the question why the supernova explosion doesn't re-collapse. A supernova explosion begins with the collapse of the core of a massive star --one with 15 or 20 times the sun's mass. The sudden implosion of the core sends a shock wave outward that blows away the outer layers of the star.

But, says Colgate, as the shock proceeds it should meet discontinuities, boundaries between layers of different density. Eventually it should come to a layer 10 times its own density. That should reflect the shock, and the blow-back should cause much or all of the matter in the star's mantle to collapse back onto the core.

Observation, shows, however, that supernova explosions continue to expand. The only way to provide for this, Colgate says, is to use the magnetic energy of the collapsed core. With the proper amount of mass, the core collapses into a neutron star, and if it rotates and has the proper magnetic field, the neutron star will be a pulsar, producing radio waves, light or X-rays that terrestrial observers see in pulses. As the pulsar rotates, its magnetic field twists up into a helical shape that fills the cavity inside the exploding supernova front. That helical shape will exert a magnetic pressure that prevents the shock front from blowing back. Furthermore, as the shock front thins out with expansion, the magnetic pressure could pierce it at some point, sending out a stream of magnetic energy into space. The stream, by encountering and energizing some interstellar matter that happened to be in the neighborhood, he says, could produce the glowing "son of supernova.'
COPYRIGHT 1987 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1987, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:supernova explosions
Publication:Science News
Date:Oct 24, 1987
Previous Article:'Out, damned spot.' (spot observed next to supernova 1987 disappears)
Next Article:New approach to treating gum disease.

Related Articles
Were the supernova's neutrinos pulsed?
Follow that supernova: as SN 1987A develops, astronomers watch and wonder.
Scientists size up supernova.
A supernova remnant around a pulsar.
Large Magellanic explosion: supernova 1987A is nature's most spectacular blast.
From massive star to supernova remnant.
A burst of new data from Supernova 1987A.
Supernova's light curve tells its tail.
ROSAT revelations: satellite provides a new view of the X-ray and ultraviolet universe.
Young pulsar has a split personality.

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters