Space

May 31, 2013

NASA’s Swift reveals new phenomenon in a neutron star

nasa-swift
Astronomers using NASA’s Swift X-ray Telescope have observed a spinning neutron star suddenly slowing down, yielding clues they can use to understand these extremely dense objects.

A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. A neutron star can spin as fast as 43,000 times per minute and boast a magnetic field a trillion times stronger than Earth’s. Matter within a neutron star is so dense a teaspoonful would weigh about a billion tons on Earth.

This neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses.

Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar’s rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate.

“Astronomers have witnessed hundreds of events, called glitches, associated with sudden increases in the spin of neutron stars, but this sudden spin-down caught us off guard,” said Victoria Kaspi, a professor of physics at McGill University in Montreal. She leads a team that uses Swift to monitor magnetars routinely.

Astronomers dubbed the event an “anti-glitch,” said co-author Neil Gehrels, principal investigator of the Swift mission at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It affected the magnetar in exactly the opposite manner of every other clearly identified glitch seen in neutron stars.”

The discovery has important implications for understanding the extreme physical conditions present within neutron stars, where matter becomes squeezed to densities several times greater than an atomic nucleus. No laboratory on Earth can duplicate these conditions. A report on the findings appears in the May 30 edition of the journal Nature.

The internal structure of neutron stars is a long-standing puzzle. Current theory maintains a neutron star has a crust made up of electrons and ions; an interior containing oddities that include a neutron superfluid, which is a bizarre state of matter without friction; and a surface that accelerates streams of high-energy particles through the star’s intense magnetic field.

The streaming particles drain energy from the crust. The crust spins down, but the fluid interior resists being slowed. The crust fractures under the strain. When this happens, a glitch occurs. There is an X-ray outburst and the star gets a speedup kick from the faster-spinning interior. Processes that lead to a sudden rotational slowdown constitute a new theoretical challenge.

On April 21, 2012, just a week before Swift observed the anti-glitch, 1E 2259+586 produced a brief, but intense X-ray burst detected by the Gamma-ray Burst Monitor aboard NASA’s Fermi Gamma-ray Space Telescope. The scientists think this 36-millisecond eruption of high-energy light likely signaled the changes that drove the magnetar’s slowdown.

“What is really remarkable about this event is the combination of the magnetar’s abrupt slowdown, the X-ray outburst, and the fact we now observe the star spinning down at a faster rate than before,” said lead author Robert Archibald, a graduate student at McGill.

Goddard manages Swift, which was launched in November 2004. The telescope is operated in collaboration with Pennsylvania State University in University Park, Penn., the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Va. International collaborators are in the United Kingdom and Italy, and the mission includes contributions from Germany and Japan.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines July 23, 2014

News: Israel’s Iron Dome defense in line for tripled U.S. spending - Israel’s iron Dome missile defense system may end up getting triple the U.S. funding that the Defense Department sought for it in March. Ukraine asked U.S. for systems to counter Russian missiles - A month before the United States says a Russian missile likely brought...
 
 

News Briefs July 23, 2014

U.S. military deaths in Afghanistan at 2,194 As of July 22, 2014, at least 2,194 members of the U.S. military had died in Afghanistan as a result of the U.S.-led invasion of Afghanistan in late 2001, according to an Associated Press count. The AP count is three less than the Defense Department’s tally. At least...
 
 
Raytheon photograph

Raytheon completes key Air, Missile Defense Radar reviews

Raytheon photograph Partially-populated, full-sized Air and Missile Defense Radar array. Raytheon has completed two critical program reviews for the new Air and Missile Defense Radar, the U.S. Navy’s next generation integ...
 

 
Insitu photograph

Insitu demonstrates long endurance capabilities of Integrator unmanned aircraft

Insitu photograph Insitu’s Integrator unmanned aircraft recovers via SkyHook; the aircraft recently completed a 24-hour endurance flight. Insitu announced July 22 the successful 24-hour flight of its Integrator unmanned a...
 
 

NASA partners punctuate summer with spacecraft development advances

Spacecraft and rocket development is on pace this summer for NASA’s aerospace industry partners for the agency’s Commercial Crew Program as they progress through systems testing, review boards and quarterly sessions under their† Space Act Agreements with the agency. NASA engineers and specialists continue their review of the progress as the agency and partners move...
 
 

U.S. Navy selects Northrop Grumman for ship self-defense system

The U.S. Navy has awarded Northrop Grumman a $12 million task order for a full range of engineering services to continue modernizing the Ship Self-Defense System Mark 2. The contract has a potential value of $61 million over five years, if all options are exercised. SSDS MK2 is a combat system designed for anti-air defense...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>