First, the “Cow” was discovered, but it appears that a small herd is gathering up!
A celestial flare-up with a funny nickname has recently gotten a company in the form of two similarly unusual outbursts.
The peculiar events were even brighter than usual supernovas. The new bursts of light came and went rapidly. Their light output has brightened and dimmed over a few days, instead of weeks, as supernovas tend to do.
The origins of the three spectacular bursts are yet to be known. However, they appear to be kin.
Astronomer Anna Ho of Caltech said: “It’s like people going out to find different creatures and find out how they’re related to each other. We’re in the early stages of the ‘zoology’ of this class.”
The Cow was detected in June 2018 and earned its nickname because of the automatically assigned astronomical name “AT2018cow.” The “Koala joins it,” also named for the ending letters of its name “ZTF18abvkwla.”
The third event, however, was reported in the May 20 edition of Astrophysical Journal Letters but did not get any cute nicknames. It is known as “CSS161010,” and it was the first our of the three to be discovered in 2016, but its importance wasn’t understood until the other two were observed.
The reason why the events happened is that they are the consequence of an unusual kind of supernova that explodes into a dense shell of material.
All the three events have been discovered with the help of telescopes, which detected radio waves as well as a short-lived flare of visible light. The radio waves might be the byproduct of accelerated electrons, which were kicked up when a blast of debris from the explosion intersected the surrounding shell.
Such phenomenons can be produced by aging stars that shed their outer layers before exploding.