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Biggest stars produce strongest magnets
SpaceFlightNow ^ | January 28, 2005 | HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

Posted on 01/30/2005 1:17:24 PM PST by Willie Green

For education and discussion only. Not for commercial use.

Astronomy is a science of extremes - the biggest, the hottest, and the most massive. Today, astrophysicist Bryan Gaensler (Harvard-Smithsonian Center for Astrophysics) and colleagues announced that they have linked two of astronomy's extremes, showing that some of the biggest stars in the cosmos become the strongest magnets when they die.

"The source of these very powerful magnetic objects has been a mystery since the first one was discovered in 1998. Now, we think we have solved that mystery," says Gaensler.

The astronomers base their conclusions on data taken with CSIRO's Australia Telescope Compact Array and Parkes radio telescope in eastern Australia.

A magnetar is an exotic kind of neutron star--a city-sized ball of neutrons created when a massive star's core collapses at the end of its lifetime. A magnetar typically possesses a magnetic field more than one quadrillion times (one followed by 15 zeroes) stronger than the earth's magnetic field. If a magnetar were located halfway to the moon, it could wipe the data from every credit card on earth.

Magnetars spit out bursts of high-energy X-rays or gamma rays. Normal pulsars emit beams of low-energy radio waves. Only about 10 magnetars are known, while astronomers have found more than 1500 pulsars.

"Both radio pulsars and magnetars tend to be found in the same regions of the Milky Way, in areas where stars have recently exploded as supernovae," explains Gaensler. "The question has been: if they are located in similar places and are born in similar ways, then why are they so different?"

Previous research has hinted that the mass of the original, progenitor star might be the key. Recent papers by Eikenberry et al (2004) and Figer et al (2005) have suggested this connection, based on finding magnetars in clusters of massive stars.

"Astronomers used to think that really massive stars formed black holes when they died," says Dr Simon Johnston (CSIRO Australia Telescope National Facility). "But in the past few years we've realized that some of these stars could form pulsars, because they go on a rapid weight-loss program before they explode as supernovae."

These stars lose a lot of mass by blowing it off in winds that are like the sun's solar wind, but much stronger. This loss would allow a very massive star to form a pulsar when it died.

To test this idea, Gaensler and his team investigated a magnetar called 1E 1048.1-5937, located approximately 9,000 light-years away in the constellation Carina. For clues about the original star, they studied the hydrogen gas lying around the magnetar, using data gathered by CSIRO's Australia Telescope Compact Array radio telescope and its 64-m Parkes radio telescope.

By analyzing a map of neutral hydrogen gas, the team located a striking hole surrounding the magnetar. "The evidence points to this hole being a bubble carved out by the wind that flowed from the original star," says Naomi McClure-Griffiths (CSIRO Australia Telescope National Facility), one of the researchers who made the map. The characteristics of the hole indicate that the progenitor star must have been about 30 to 40 times the mass of the sun.

Another clue to the pulsar/magnetar difference may lie in how fast neutron stars are spinning when they form. Gaensler and his team suggest that heavy stars will form neutron stars spinning at up to 500-1000 times per second. Such rapid rotation should power a dynamo and generate superstrong magnetic fields. 'Normal' neutron stars are born spinning at only 50-100 times per second, preventing the dynamo from working and leaving them with a magnetic field 1000 times weaker, says Gaensler.

"A magnetar goes through a cosmic extreme makeover and ends up very different from its less exotic radio pulsar cousins," he says.

If magnetars are indeed born from massive stars, then one can predict what their birth rate should be, compared to that of radio pulsars.

"Magnetars are the rare 'white tigers' of stellar astrophysics," says Gaensler. "We estimate that the magnetar birth rate will be only about a tenth that of normal pulsars. Since magnetars are also short-lived, the ten we have already discovered may be almost all that are out there to be found."

This press release is being issued in conjunction with CSIRO's Australia Telescope National Facility.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.


TOPICS: Astronomy; Science
KEYWORDS: catastrophism; ironsun; magnet; magnetars; magneticfield; magnetism; oliverkmanuel; olivermanuel; physics; poleshift; science; stringtheory

1 posted on 01/30/2005 1:17:24 PM PST by Willie Green
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To: blam; RightWhale; pissant

ping


2 posted on 01/30/2005 1:18:01 PM PST by Willie Green (Go Pat Go!!!)
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To: Willie Green

The Universe is fascinating!


3 posted on 01/30/2005 1:57:06 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)
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To: RadioAstronomer

ping!


4 posted on 01/30/2005 1:57:36 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)
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To: Ernest_at_the_Beach
Yeah, I never heard of a "magnetar" before...
I wonder how that term has managed to escape the notice of all the sci-fi writers for Star Trek, etc.???
5 posted on 01/30/2005 2:25:30 PM PST by Willie Green (Go Pat Go!!!)
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To: Willie Green
1 entry found for magnetar.
Main Entry:   magnetar
Part of Speech:   noun
Definition:   a young neutron star, perh. formed in supernova explosions and having an immense magnetic field; also called soft gamma repeater
Example:   Discovery of a magnetar solves 19 year mystery in astrophysics.
Etymology:   magne(tic) + (s)tar

Source: Webster's New Millennium™ Dictionary of English, Preview Edition (v 0.9.5)
Copyright © 2003, 2004 Lexico Publishing Group, LLC

*********************************************


6 posted on 01/30/2005 2:32:33 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)
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To: Willie Green
Great source here:

`MAGNETARS', SOFT GAMMA REPEATERS
& VERY STRONG MAGNETIC FIELDS

**************************************************

Robert C. Duncan, University of Texas at Austin duncan@astro.as.utexas.edu

Abstract
Soft gamma repeaters ("SGRs") are X-ray stars that emit bright, repeating flashes of soft (i.e. low-energy) gamma rays. The physical nature of these stars was a mystery for many years. In 1992, it was proposed that SGRs are magnetically-powered neutron stars, or magnetars. Subsequent observational studies lent support to this hypothesis. Astronomers now think that all emissions detected from SGRs and from a related class of stars known as anomalous X-ray pulsars ("AXPs") are powered by magnetic field decay. Here I will explain how these strange, physically-extreme stars form, and why they emit steadily pulsating X-rays with sporadic, bright outbursts. I will also tell the story of their discovery and of the theoretical efforts which helped to reveal their bizarre nature.

NOTE: this website was originally written in May 1998, in response to a surge of interest in magnetars. In early 2003 I updated the site, to answer questions raised by readers of a Scientific American cover story on magnetars. I made significant revisions throughout, and added new sections. However, I did not come close to covering all the recent progress in this rapidly-developing area of astrophysics. I am currently writing a book that will tell much more about magnetars, and explain everything more carefully and thoroughly.

- R.D., March 2003


7 posted on 01/30/2005 2:37:44 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)
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To: Willie Green

The first discoverer of the possibility of the black hole was ignored. The rediscoverer was laughed out of the lecture hall. If we could see the center of the Milky Way, the black hole accretion disk would be as bright as the full moon.


8 posted on 01/30/2005 2:46:08 PM PST by RightWhale (Please correct if cosmic balance requires.)
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To: RightWhale; Willie Green
PDF paper from 1995:

magnetars

9 posted on 01/30/2005 3:15:01 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)
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To: Willie Green

I learn something new every day.
Thank you. This is the first I have heard of a magnetar.


10 posted on 01/30/2005 3:19:04 PM PST by R. Scott (Humanity i love you because when you're hard up you pawn your Intelligence to buy a drink.)
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To: Willie Green

I bet her magnets could change magnetic North.
11 posted on 01/31/2005 8:19:19 PM PST by Andy from Beaverton (I only vote Republican to stop the Democrats)
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Note: this topic is from 1/30/2005.

· String Theory Ping List ·
721 posted on 04/24/2007 8:14:42 PM PDT by DocRock
· Join · Bookmark · Topics · Google ·
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12 posted on 07/17/2011 4:52:51 PM PDT by SunkenCiv (Yes, as a matter of fact, it is that time again -- https://secure.freerepublic.com/donate/)
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To: 75thOVI; agrace; aimhigh; Alice in Wonderland; AndrewC; aragorn; aristotleman; Avoiding_Sulla; ...
Note: this topic is from 1/30/2005.



13 posted on 07/17/2011 4:52:55 PM PDT by SunkenCiv (Yes, as a matter of fact, it is that time again -- https://secure.freerepublic.com/donate/)
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To: SunkenCiv

Is that a message to Planet Earff?


14 posted on 07/17/2011 4:58:03 PM PDT by Monkey Face (Nothing is so bad that a good skirl on the Pipes can't cure! Long live sionnsar!)
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To: Monkey Face

Looks that way. :’)


15 posted on 07/18/2011 3:23:00 AM PDT by SunkenCiv (Yes, as a matter of fact, it is that time again -- https://secure.freerepublic.com/donate/)
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