A Star That Bursts, Blinks and Disappears

A Star That Bursts, Blinks and Disappears
This illustration shows a flare from magnetar Swift J195509+261406. A starquake is probably what triggered the object's 40 optical flares. Credit: NASA/Swift/Sonoma State University/A. Simonnet

(PhysOrg.com) -- "Twinkle, twinkle little star" goes the nursery rhyme. Now, astronomers are reporting on a strange case where one of the littlest of stars "twinkled" with gamma rays, X-rays, and light -- and then vanished.

The story began on June 6, 2007. That’s when a spike of gamma-rays lasting less than five seconds washed over NASA's Swift satellite. But this high-energy flash wasn't a gamma-ray burst -- the birth cry of a black hole far across the universe. It was something much closer to home.

Swift immediately reported the event’s position to astronomers all over the world. Within a minute, robotic telescopes turned to a spot in the constellation Vulpecula. Because Swift found an X-ray glow coming from this point, astronomers cataloged the object as "Swift J195509+261406," after its position in the sky and the discovering satellite. (Well, they had to call it something!)

During the next three days, the object brightened and faded in visible light. Not once, not twice -- but 40 times! Eleven days later, it flashed again, this time at infrared wavelengths. Then, it disappeared from view.

"I love it when Swift enables a discovery like this," says Neil Gehrels, the mission's lead scientist at NASA Goddard Space Flight Center in Greenbelt, Md. "The observatory is an astronomical robot built for gamma-ray burst studies, but it can also quickly point at other bizarre objects with bright flares."

Astronomers think the object was a neutron star -- the crushed innards of a massive star that long ago exploded as a supernova -- about 15,000 light-years away. Writing in the Sept. 25 issue of the science journal Nature, a team of 42 scientists concludes that Swift J195509+261406 is a special type of neutron star called a magnetar.

"We are dealing with an object that was hibernating for decades before entering a brief activity period," explains Alberto J. Castro-Tirado, lead author of the paper. "Magnetars remain quiet for decades."

Although measuring only about 12 miles across -- about the size of a city -- neutron stars have the strongest magnetic fields in the cosmos. Sometimes, those magnetic fields are super strong -- more than 100 times the strength of typical neutron stars.

Astronomers put these magnetic monsters in their own class: magnetars. Only about a dozen magnetars are known, but scientists suspect our galaxy contains many more. We just don’t see them because they’re quiet most of the time.

So what happened last year? Why did this previously unseen star begin behaving so badly? And why did it stop?

Combine a magnetar's pumped-up magnetic field with its rapid spin, and sooner or later something has to give. Every now and then, the magnetar’s rigid crust snaps under the strain.

This "starquake" releases pent-up magnetic energy, which creates bursts of light and radiation. Once the star’s crust and magnetic field settle down, the star goes dark and disappears from our view. At least until the next quake.

Astronomers suspect that magnetars lose their punch as time passes, but Swift J195509+261406 provides the missing link between objects exhibiting regular activity and those that have settled into retirement -- and invisibility.

So twinkle, twinkle magnetar. That's how we'll learn just where you are.

Provided by NASA's Goddard Space Flight Center

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Citation: A Star That Bursts, Blinks and Disappears (2008, September 30) retrieved 15 October 2019 from https://phys.org/news/2008-09-star.html
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Sep 30, 2008
This is a bit unrelated, but what is the nature of brain waves... are they a form of light like other radiation?

Sep 30, 2008
Two papers posted at the arXiv.org site for September 25 (arXiv:0809.4043 and arXiv:0809.4231) describe in detail the observations made of this strange object. It seems that this may be the first-ever sighting of a magnetar in the optical band of the EM spectrum. The cause of the optical-IR flaring still remains a mystery, but it is noted that few theoretical models exist that might explain the visible-light outbursts. Also, no x-ray flaring was detected during the optical outbursts, contrary to previously observed x-ray variability of suspected magnetars in outburst. Some have hypothesized that magnetar outbursts could be caused by comets, asteroids or even planets crashing onto the surface of a neutron star. With this magnetars unusual signature,'starquakes' may fit the bill, though another theory is entertained in the second paper mentioned above. Quite a mysterious object indeed!

Sep 30, 2008
Ah! In habitants of a planet orbiting that star obviously were playing with advanced particle accelerators and .....

Sep 30, 2008
That's a really odd object:). I'm amazed that they are able to redirect telescopes to view something like this in under a minute! That's just cool.

Oct 01, 2008
Oderfla, um, no, brain waves are cycles in the signalling activity in our neural structures.

Oct 01, 2008

Oct 29, 2008
Well, another sucesfull LHC test made by some ancient civilisation...

May 20, 2009
you are not alone ii seenone in the souther sky about 10:20pm may 20 2009. it was the first star i looked at i watched it get brighter then it fade away it lasted about 2 to 3 seconds.i keep looking thinking my eyes were playing tricks but it never reappeared.i started thinking it was the light but i could still see the stars around it just fine. so i googled it and it lead me hear.please take me serious.i have never witnessed anything like it.i know i'm not crazy. does this stuff happen all the time? it happened so fast. but it did just as i said didnt move just faded

May 21, 2009
jerome769: That sounds like an Iridium Flash. The Iridium Network is a large network of communications satellites. They are very dull, except for one little part of them which is really shiny. As they spin in space every now-and-again the shiny side mirrors the light from the Sun down to Earth. It looks like a *very* bright flash, lasting 2-3 seconds. They're really cool:).

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