Type la supernovae, also labelled as “zombie stars,” are a group of special neutron stars that explode as they die and then revive themselves by consuming the energy of nearby stars. They are called “zombies” because they are dead but come back to life by sucking the matter out of other stars.
These stars are not unique in anyway and are, instead, common occurrences in the universe, although there are only five known zombie stars, four in our Milky Way Galaxy and one in a neighboring satellite galaxy.
They were first discovered in 1054 when a star exploded and formed into the supernova remnant, crab nebula. These stars can become so bright that they shine as much as one billion suns. The latest incident occurred in 2005 when an explosion 50,000 light-years away caused a brief alteration of our upper atmosphere.
These stars are approximately between 10 km (6 miles) and 30 km (20 miles) in diameter, have twice the mass of our sun and contain magnetic fields that are up to 1,000 times stronger.
“At times, this remarkable object has erupted with more than a hundred flares in as little as 20 minutes,” said research associate at the Pennsylvania State University, Loredana Vetere, said in a statement related to NASA’s Swift satellite project. “The most intense flares emitted more total energy than the sun does in 20 years.”
Over the last 50 years, astrophysicists have concluded that they are part of binary systems – a system where two stars orbit one another. It’s believed that the exploding star is actually a white dwarf star.
One hypothesis put forth suggests that due to the presented mass, two white dwarf stars could have merged and created the binary system. As time progresses, the two stars spiral into each other, merge and then explode.
This special category of stars is crucial to understanding the mystery of dark energy in space.
In an interview with Physorg.com, astrophysicist Andy Howell explained that scientists are utilizing Type la supernovae to construct a map of the history of our universe’s expansion.
“And it [universe] hasn’t been slowing down as everyone thought it would be, due to gravity,” said Howell, who is also a staff scientist at Las Cumbres Observatory Global Telescope (LCOGT). “Instead, it has been speeding up. There’s a force that counteracts gravity and we don’t know what it is. We call it dark energy.”
Although it is indeed possible to see these stars with the naked eye, scientists are utilizing digital cameras on their massive telescopes that will assist in the detailed study of both zombie stars and dark energy.