Scientists have uncovered evidence of an incident involving asteroids bombarding a tiny pulsar 73,000 thousand light years away. One of the asteroids that crashed into the star had an estimated mass of approximately one billion tons.
The pulsar in question is called PSR J0738-4042. A pulsar, which name comes from a combination of the words pulsating and star, is a tiny neutron star that can emit powerful beams of electromagnetic radiation. It is this special ability to emit highly energized beams of radiations that helped the PSR JO38-4042 escape from its encounter with a group of asteroids relatively unscathed.
"One of these rocks seems to have had a mass of about a billion tonnes," said Dr. Ryan Shannon, an astronomer from the Commonwealth Scientific and Industrial Research Organization (CSIRO).
Pulsars are known to pulsate at known rates causing a visual effect similar to twinkling stars. Due to the precise nature of the period of these pulses, pulsars are known to be some of the most accurate "clocks" in the universe. However, scientists have theorized that certain astronomical events can trigger a slight change in the normally precise pulses emitted by a pulsar. Back in 2008, Shannon and another researcher tried to predict how an asteroid of sufficient mass would affect a pulsar during a collision. They theorized that the encounter could lead to a slowing down in the rate at which a pulsar rotated.
"This is exactly what we see in this case," said Shannon.
So how can a pulsar survive a collision with a group of asteroids including a giant space rock with a mass of more than a billion tons? Shannon and his colleagues seem to think that the pulsar vaporized the asteroids with powerful beams of radiation.
"We think the pulsar's radio beam zaps the asteroid, vaporising it. But the vaporised particles are electrically charged and they slightly alter the process that creates the pulsar's beam," said Shannon.
The researchers also believe that the same pulsar that vaporized the giant space rocks, created the asteroids in the first place. The asteroids could have formed from the explosion that created the pulsar millions or even billions of years ago. A pulsar is created when a massive star goes supernova. The explosion generates a large gas cloud that can condense and form asteroids around a newborn pulsar.
"This sort of dust disk could provide the 'seeds' that grow into larger asteroids," said Paul Brook, the leader of the study and a PhD student supervised by the University of Oxford and CSIRO.
The researchers have published their findings in the online journal The Astrophysical Journal Letters.