The question as to who killed the radio star has finally been answered — it wasn’t killed, it committed suicide by changing itself into a black hole, just like many other radio stars. According to researchers in a December 20 press release, a certain kind of radio star turns off its radio transmission prior to going ka-bloo-ie, falling in upon itself, and changing into a black hole, while other radio stars turn into neutron stars.
As they explode, the radio stars let out one last hurrah in the form of a powerful burst of gamma rays, according to a Curtin University press release.
The most recent example that the researchers wrote about in an upcoming research paper was somewhat different from others, in the gamma ray burst wasn’t followed by a spooky afterglow. The researchers were surprised, because they had set out trying to prove that the gamma burst the followed the explosion of a radio star would always result in a radio afterglow.
What the research team ended up writing about in their study was that the previous theory about the radio afterglows that always followed the death of radio stars was incorrect, according to lead researcher Dr. Paul Hancock.
Hancock and his research team offered up a new theory, that there are two types of gamma ray bursts that can follow the explosion and death of a radio star, leading to its transformation into a black hole. The type of gamma ray burst, they believe, has to do with the magnetic field of the exploding star. Some radio stars transform upon their deaths into black holes, while others change into neutron stars, which have even stronger magnetic fields than black holes.
Both black holes and neutron stars have super-dense cores, but, according to Hancock, neutron stars have magnetic fields “a million times stronger than those of black holes.” Because of these stronger magnetic fields, “producing gamma rays are more difficult.”
Hancock and his research team’s soon-to-be published study indicates that the radio stars that die and become neutron stars ” have energy left over to produce the radio afterglow” while the radio stars which become black holes “put all their energy into one final powerful gamma-ray flash.”
The next task that Hancock and his colleagues want to tackle is discovering the differences between the two examples of gamma ray blasts. Finding out what these differences are will make it easier to differentiate between which type results in black holes and which results in neutron stars.
The research findings of Hancock and his team are in an online preprint article called “Two populations of gamma-ray burst radio afterglows.” You can read the full pdf article at the link below.
The old theory about afterglows following the deaths of all radio stars was proven to be incorrect. The new theory that Hancock and his research team have replaced it with says that the death of radio stars and the gamma-ray bursts that follow may or may not result in afterglows, depending on if they are transformed into neutron stars or black holes.
Written by: Douglas Cobb