-
-
--------------------------------- 2600 - MAGNETARS - magnetic stars?
-
- More than 60 years ago astronomers have realized about 10 percent of massive stars have powerful magnetic fields bursting from their surfaces. But the exact origins of these magnetic fields, which can reach hundreds to thousands of times the strength of the Sun's magnetic fields has so far remained a mystery.
-
- They may be due to a collision between two normal stars. Magnetism itself is a mystery. We learned that a refrigerator magnet is created when the atoms in a metal all line up in a particular direction causing a net magnetic force. And, that the little magnet stuck to the refrigerator is so powerful it can over come the pull of gravity coming from the mass of the entire Earth.
-
- Magnetism is 1,000 times stronger than the force of gravity
-
- Magnets created by massive stars are called “magnetars“. These magnetic mergers occur when two stars collide, it sends the star surfaces spinning and simultaneously kicks off enormous amounts of turbulence. This dramatically boosts the final star’s magnetic field.
-
- As the star spins, its inner layers rotate faster than its outer layers, a process called differential rotation. Running through and connecting each of these layers are magnetic field lines. Because each layer rotates at a different speed, the magnetic field lines connecting the layers get twisted and tangled up. This serves to amplify the overall strength of the magnetic field.
-
- This turbulence further stirs the magnetic field lines, exponentially increasing the star's magnetism. “Blue stragglers” are a unique class of stars that masquerade as stars younger than they truly are. These "rejuvenated" stars are much hotter, much bluer, and brighter than your average main-sequence middle-aged star of a similar apparent age.
-
- But the fountain of youth that keeps blue stragglers looking so fresh is a mystery? A leading theory is that merging with another star will do the trick. The typical main-sequence stars power themselves by fusing hydrogen into helium in their cores. But when the hydrogen in their cores runs out, they move on to fusing concentric shells of hydrogen around their now-inert cores. This causes the star to balloon up into a red giant, moving it off the main-sequence and into the so-called red giant branch.
-
- But if two main-sequence stars collide, their material gets mixed together. The resulting merged product now has a restocked reservoir of hydrogen in its core, which allows it to expand along as a more massive, yet still main-sequence , blue straggler instead of evolving into a red giant.
-
- This means that post-merger stars have more nuclear fuel to then live longer. But that only makes the newly formed star appear younger. The blue straggler could have lived for a long time as lower-mass stars and then merged to become this more massive blue straggler. It’s high mass fooling us into thinking it must be younger.
-
- Scientists first suggested a collision between two stars could generate strong magnetic fields more than a decade ago. But until now, astronomers were not able to test this hypothesis because they didn't have the necessary computational tools. But thanks to the newest computer programs the researchers are finally able to show that two merging stars, which originally lacked much magnetism, can join forces and create a new, highly magnetize star.
-
- These studies show that massive blue straggler stars seem likely to be the progenitors of magnetars, perhaps giving rise to some of the enigmatic fast radio bursts observed, and their supernovae may be affected by their strong magnetic fields."
-
- Magnetars are a rare breed of neutron stars with absurdly powerful magnetic fields that reach some 5 quadrillion (one quadrillion is 1,000 trillions) times stronger than Earth's. Magnetars are thought to have the strongest magnetic fields in the universe.
-
- Magnetars could be the natural end product of main-sequence stars and probably also pre-main-sequence mergers. The biggest and yet-unsolved question is whether the magnetic field produced in the merger can survive up to the supernova stage, and then whether the magnetic field is indeed maintained in the forming neutron star when the core of the star collapses.
-
- This still needs to be seen. The research goes on. Astronomy is finally beginning to understand the origin of magnetars and their strong magnetic fields.
-
- Other reviews about magnetism available upon request:
-
- 2341 - Magnetism is one manifestation of the electromagnetic force, which is one of the four forces known in the universe. All material that we know of is magnetic at some level. The electrons spin about the atom and the electrons themselves spin so that each atom becomes a tiny atomic magnet. To go from the smallest to the very largest magnetic fields we need to go from atoms to stars.
-
- 2154 - Magnetism is a force that exerts attractive or repulsive force on other materials. All materials are influenced to a greater or lesser degree by the presence of a magnetic field. All materials! Magnets come in two basic types, permanent magnets and electromagnets. Magnetism is ultimately the result of movement of an electric charge. The most common use of Nuclear Magnetic Resonance is in medicine.
-
- 1878 - Magnetic structures in the Galaxies. New mysteries are uncovered to understand how magnetic fields throughout galaxies affect star formation and galactic structure. New tools are creating 3-D maps. Dark Matter remains 85% of the undiscovered.
- 1383 - Magnetars are lethal Neutron Stars.
- 1223 - Where do big stars go when they die?
- 1159 - What are Magnetars?
- 704 - Magnetars in the heavens.
-
- January 30, 2020 2600
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
- https://plus.google.com/u/0/ -- www.facebook.com -- www.twitter.com
--------------------- Friday, January 31, 2020 --------------------
-----------------------------------------------------------------------------------------
No comments:
Post a Comment