Although the pair was discovered in 2006 and 2007 the supernovae were so unusual that astronomers initially could not figure out what they were or even determine their distances from Earth. Scientists affiliated with the Supernova Legacy Survey (SNLS) spent years trying to figure out what these strange things were. Their findings appear in the Dec. 20 issue of the Astrophysical Journal.
"At first, we had no idea what these things were, even whether they were supernovae or whether they were in our galaxy or a distant one," said lead author D Andrew Howell, a staff scientist at Las Cumbres Observatory Global Telescope Network (LCOGT) and adjunct faculty at UC Santa Barbara. "I showed the observations at a conference, and everyone was baffled. Nobody guessed they were distant supernovae because it would have made the energies mind-bogglingly large. We thought it was impossible."
One puzzle still remains - what is the source of power that can generate so much energy? The mechanism that powers most supernova - the collapse of a giant star to a black hole or normal neutron star-cannot explain their extreme luminosity.
The new study finds that the supernovae are likely powered by the creation of a magnetar, an extraordinarily magnetized neutron star spinning hundreds of times per second. Magnetars have the mass of the sun packed into a star the size of a city and have magnetic fields a hundred trillion times that of the Earth. While a handful of these superluminous supernovae have been seen since they were first announced in 2009, and the creation of a magnetar had been postulated as a possible energy source, the work of Howell and his colleagues is the first to match detailed observations to models of what such an explosion might look like.
"What may have made this star special was an extremely rapid rotation," Daniel Kasen from UC Berkeley and Lawrence Berkeley National Lab said. "When it ultimately died, the collapsing core could have spun up a magnetar like a giant top. That enormous spin energy would then be unleashed in a magnetic fury."
The supernovae exploded when the universe was only 4 billion years old. "This happened before the sun even existed," Howell explained. "There was another star here that died and whose gas cloud formed the sun and Earth. Life evolved, the dinosaurs evolved and humans evolved and invented telescopes, which we were lucky to be pointing in the right place when the photons hit Earth after their 10-billion-year journey."
Anda sedang membaca artikel tentang
Pair of exploding stars found 10 billion light years away
Dengan url
http://pijitwajah.blogspot.com/2013/12/pair-of-exploding-stars-found-10.html
Anda boleh menyebar luaskannya atau mengcopy paste-nya
Pair of exploding stars found 10 billion light years away
namun jangan lupa untuk meletakkan link
Pair of exploding stars found 10 billion light years away
sebagai sumbernya
0 komentar:
Posting Komentar