Shockingly Bright Dead Star

[Waspie_Dwarf]

NASA’s NuSTAR Telescope Discovers Shockingly Bright Dead Star

Astronomers have found a pulsating, dead star beaming with the energy of about 10 million suns. This is the brightest pulsar – a dense stellar remnant left over from a supernova explosion – ever recorded. The discovery was made with NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.

"You might think of this pulsar as the 'Mighty Mouse' of stellar remnants," said Fiona Harrison, the NuSTAR principal investigator at the California Institute of Technology in Pasadena, California. "It has all the power of a black hole, but with much less mass."

Read more...

[Waspie_Dwarf]

Beacons of X-ray Light

This animation shows a neutron star -- the core of a star that exploded in a massive supernova. This particular neutron star is known as a pulsar because it sends out rotating beams of X-rays that sweep past Earth like lighthouse beacons. X-ray telescopes like NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, pick up these beams, registering them as pulses of X-ray light.

What causes a pulsar to pulse? In the case of "accreting pulsars," the process is set in motion when matter from a companion star falls onto the pulsar. The gravity of the pulsar pulls this material from a surrounding disk, as shown in the animation. The strong magnetic fields surrounding the pulsar funnel the infalling material onto two spots above and below the stellar core. This causes the material to heat up to extreme temperatures and release X-rays. As the star rotates, the two X-ray hot spots behave like a lamp in a lighthouse, sweeping around. Only when the "lamps" are facing Earth will NuSTAR pick up the signal -- a pulsing of X-rays.

Credit: NASA/JPL-Caltech

Source: NASA - Multimedia

[bison]

It's been reported that this object, M82 X2, has an average pulsing period of 1.37 seconds, and that this varies a bit in a gradual and regular way (sinusoidally) over a period of about 2 and a half days. This seems to indicate a stellar-scale companion object with an orbital period of about that length.

This would support the working hypothesis that the this object is an accretion-powered pulsar, where a neutron star is pulling in material from a old companion star that has expanded beyond the point of dynamical stability.

It does not appear that this can account for the 100 fold energy output in x rays, over what could be predicted for such a system, given the mass of the pulsar.

[bison]

The minimum width of the energy beams expected from a pulsar seems to be about 5 degrees. Perhaps if these were much narrower than usual, in this case, it would make the pulsar appear much more powerful than is considered possible. Of course, we would then have to explain why the beams should be so much narrower than in any of the multitude of other pulsars that have been observed. These would have to amount to something almost like an x ray laser beam.