Exploding Neutron Star

Mick Ohrberg writes "According to NASA News, scientists at NASA and CITA are watching a neutron star (4U 1820-30, 25,000 light years from Earth) explode. Or rather - watch an explosion happen just a few miles above the surface of this immensely dense body. What happens is that matter (mostly helium) from a companion star is by the gravity of the neutron star and collected on the surface until a layer is formed and sufficient pressure is generated. This will cause the helium to fuse into carbon and other elements, releasing enormous amounts of energy in the X-ray band. The event was caught using NASA's Rossi X-ray Timing Explorer. More details can be found here."

Comments

Additional Linkage

[brownpau]

CG animation and screencaps here:
http://www.gsfc.nasa.gov/topstory/2004/0220 stardis k.html

Re:Isn't this called a Nova?

[QuantumFTL]

I am not aware of any other uses for the term "nova" than in "supernova".

Along with the ordinary use of "nova" there is also something called a hypernova. Think of it as a supernova's big brother.

I was privileged enough to be at the colloquium where Hans Bethe unveiled his theory about hypernovae and gamma ray bursts. You can find an interesting paper on hypernova at Cornell's arxiv.org.

Cheers,
Justin Wick

P.S. The papers done the research group I'm in at Cornell talk about things similar to this accretion process. They can be found here.

Don't Forget...

[dnahelix]

It really happened 25,000 years ago!

Re:Isn't this called a Nova?

[mbrother]

There are many types of "nova" if you include everything with that name. There are supernova, dwarf nova, hypernova, etc. The garden variety nova is from hydrogen fusion on the surface of a white dwarf star, normally in a binary system with mass transfer. Dwarf nova happen in the accretion disks in binary systems. Supernova can happen in single, massive stars at the end of their lives (type II), or in white dwarf binary systems when enough mass transfer makes the white dwarf collapse, probably to form a neutron star (type I). I'll go ahead and plug my novel Star Dragon (see my webpage link) which takes place in the dwarf nova system SS Cygni and explains some of this in a work of fiction.