All you need to know about Kilonovas

All you need to know about Kilonovas

Kilonovas have already answered a lot of long-lasting mysteries and there is certainly a lot more to come.

Let’s delve deep into what seems something straight out of a sci-fi movie. Gone are the times when a ‘Supernova’, a blast when a star dies, was the only cool thing around. Now we have ‘Kilonovas, which are formed when a neutron star (collapsed core of a dead star) and a black hole or two neutron stars merge. This colossal explosion, although not as bright as a Supernova, produces the most powerful electromagnetic waves known to us. This cosmic event was discovered this Monday and spread lightning-fast throughout the scientific community.

A neutron star is formed from the remnants of a dead star. When a star dies, it explodes, obliterating its outer surface. The remainder of the inner core forms a dense body called a neutron star. It generates enough gravity to crush itself till its protons and electrons compact and form neutrons. While the two neutron stars witnessed were relatively small, each of them contained as much matter as the Sun. The original name for this explosion was ‘Macronova’, which undoubtedly sounded ‘stupid’ as acknowledged by Andy Howell, an Astronomer at the University of California. He said,

“We’re so early we don’t have the terminology sorted out.”

Eventually, the term ‘Kilonova’ was coined and let’s all agree, it sounds way cooler. This fireball arose after a short-term (1/10 of a second) gamma-ray burst came into view of the Swift Space Telescope on the 3rd of June. After the collision, a massive amount of radioactive matter ejected outwards. This mass is usually composed of the matter that is not abundant in our universe. This Kilonova generated enough gold and uranium to fill the Earth about 10,000 times over. The neutron-rich gas emitted, rapidly forms heavy elements like uranium, gold, and platinum.

An analogy was used to understand this completely. Say you have a tube of toothpaste with holes on both ends. What would happen if you were to smash your fist on the tube? A considerable amount of toothpaste would come out of both holes. Now scale this to the size of a cosmic event. The amount of toothpaste floating in space would be insanely huge. According to some theories, the neutron stars were once twin suns in a solar system. They orbited each other and drifted closer and closer until gravity smashed them together. Scientists have always wondered how the most precious metals in the universe were formed and now we have evidence suggesting that Kilonovas are in fact, the foundries for these metals.

Kilonovas also answered a few of the questions that the astronomers had over the years since they detected gamma-ray bursts throughout space. The Kilonovas were put in theory but it wasn’t until now that we have solid evidence to support those theories. The Kilonova theories still have a substantial number of unknowns so it can be concluded that much of the work is being done on assumptions. Roy Kilgard, a Wesleyan Research Associate Professor of Astronomy acknowledged that by saying,

“It is incredibly rare to observe a new phenomenon for the first time. Gravitational wave observatories like LIGO have completely changed the way we think about astrophysical unsolved problems now. More observations about the size constraints of neutron stars will be necessary to answer this question.”

Several conclusions have been drawn from this event. Two seconds following the detection of gravitational waves, the NASA Fermi Telescope detected a short gamma-ray burst. These observations led scientists to conclude gamma-ray bursts of about two seconds are produced when neutron stars merge. Furthermore, these simultaneous signatures of gravitational waves and short gamma-ray bursts confirm Einstein’s prediction that gravitational waves travel at the speed of light. Nial Tanvir of the University of Leicester expressed his views in the following words:

“This observation finally solves the mystery of the origin of short gamma-ray bursts. Many astronomers, including our group, have already provided a great deal of evidence that long-duration gamma-ray bursts (those lasting more than two seconds) are produced by the collapse of extremely massive stars. But we only had weak circumstantial evidence that short bursts were produced by the merger of compact objects. This result now appears to provide definitive proof supporting that scenario.”

The question that remains is, are Kilonovas or similar stellar blasts responsible for all the metals found in our universe?

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