Blog Categories

About Us

AceMagnetics.com has become the premier magnetic bracelet, copper bracelet and magnetic jewelry online catalog as a result of our commitment to one simple tenet - customer service.
Continue

Recent Posts

Blog Archive

  1. August 20151 Posts
  2. March 20151 Posts
  3. June 20141 Posts
  4. December 20131 Posts
  5. November 20131 Posts
  6. August 20131 Posts
  7. March 20132 Posts
  8. December 20121 Posts
  9. November 20121 Posts
  10. August 20121 Posts
  11. December 20111 Posts
  12. November 20112 Posts
  13. October 20113 Posts
  14. September 20111 Posts
  15. August 20113 Posts
  16. June 20111 Posts
  17. April 20112 Posts
  18. March 20113 Posts
  19. February 20112 Posts
  20. January 20115 Posts
  21. December 20102 Posts
  22. November 20101 Posts
  23. October 20105 Posts
  24. August 20105 Posts
  25. June 20101 Posts
  26. May 20101 Posts
  27. April 20101 Posts
  28. March 20104 Posts
  29. February 20105 Posts
  30. January 20106 Posts
  31. December 20096 Posts
  32. October 20096 Posts
  33. September 20095 Posts
  34. August 20096 Posts
  35. July 200912 Posts
  36. June 20094 Posts
  37. May 20096 Posts
  38. April 20095 Posts
  39. March 200910 Posts
  40. February 20094 Posts
  41. January 20094 Posts
  42. December 20089 Posts
  43. November 20084 Posts
  44. October 20081 Posts
  45. September 20086 Posts
  46. August 20082 Posts
  47. July 20081 Posts
  48. April 20081 Posts
  49. February 20083 Posts
  50. January 20089 Posts
  51. December 20074 Posts
  52. September 20072 Posts
  53. August 20071 Posts
  54. July 20073 Posts
  55. June 20079 Posts
  56. May 200719 Posts
  57. April 200734 Posts
  58. March 200748 Posts
  59. February 200722 Posts
  60. January 20077 Posts
  61. December 20061 Posts
  62. November 200622 Posts
  63. October 200611 Posts
  64. September 20062 Posts
  65. August 20065 Posts

Apr 17

Mystery of Magnetic Stars Solved


 

While you may never have pondered the similarity between a common bar magnet and a star, astronomers do, and they believe they have figure out why the two disparate bodies are sometimes strikingly similar.

Magnetic activity on many stars, such as our Sun, varies a lot over days, weeks and years. Magnetic fields pop in and out of existence at different spots and overall intensity changes with time. But other stars have strong, consistent magnetic fields that behave just like the smooth and static field of a bar magnet. Astronomers call them magnetic stars.

In these magnetic stars, as with bar magnets, magnetic field lines emanate from each pole, north and south, and loop outward like the skeletal lines of a perfect pumpkin, connecting one pole to the other.

There are three types of magnetic stars:

  • Magnetic A-stars are otherwise normal and about two to 10 times as hefty as the Sun. One example is Alioth, the third star in on the handle of the Big Dipper.
  • Some white dwarfs, which are burnt-out stellar corpses, have magnetic fields 100,000 times stronger than the typical magnetic A-star.
  • Magnetars are ultra-dense neutron stars that have fields 100 billion times stronger than a commercial bar magnet.

For the past five decades or so, there have been two competing ideas for how magnetic stars pack such strong and consistent power. One says the magnetism is generated by movement deep within the star, similar to how Earth's ever-present magnetic field is created.

The other idea, known as the fossil field hypothesis, holds that the magnetic field of a giant gas cloud is sometimes retained after the cloud collapses to form a star. That fits with the fact that fields of magnetic stars don't change with time. But there's a problem: The magnetic field in a star should decay in a few years, other theories state, so something would have to rejuvenate it. Or, perhaps the theory hasn't been fully fleshed out.

Researchers at the Max Planck Institute for Astrophysics have made new numeric simulations in which magnetic fields of various initial configurations become stable as a star develops, supporting the fossil field idea.

"The clouds from which stars form contain a very large amount of magnetic field lines, more than even the stars with the strongest fields observed, explained Max Planck researcher Hendrik Spruit. "Most of the magnetic flux decays away in all cases, but in some a bit (or even a lot) remains."

The fields always end up the same, with a ring of twisted field lines. The mess looks something like a car tire in which broken steel from the internal wire mesh sticks through the surface at various angles, Spruit and his colleagues reported in the Oct. 14 issue of the journal Nature. ....Read on....http://www.space.com/scienceastronomy/magnetic_stars_041102.html

Posted by Jay Roberts at 04:04 AM | Permalink

TrackBack

TrackBack URL for this entry:
http://site.acemagnetics.com/blog-mt/mt-tb.fcgi/157