A recent study has shown that stars on their way to attaining the supernova become unstable. They start becoming unsteady and remain that way for months before finally exploding. In the process, they spew materials into space and also form a dense overlay of gas around them.

According to Science Daily, the most common type of supernova sees the iron core of a massive star suddenly collapsing, spitting out the layers on the outside into space in an extraordinary explosion. Researchers say that the stars attaining core-collapse might start showing signs of instability months before the supernova explosion takes place. The list includes even the most massive stars in the universe, as well as the red supergiants, who are termed as the main initiator of the supernova process.

Researchers opine that to detect the core collapse of a star, the most important thing is observation. It is very crucial as it lets the scientists understand the materials surrounding the stars before the explosion happens. Reportedly, a star attaining the phase of supernova becomes unstable for almost a year, which leads to shelling out of materials into the space forming a shell of gas around the star.

According to Daily Galaxy, the researchers detected the time period of instability of a star attaining supernova by comparing the observed data received from early spectra and light curve data with existing models, which was accompanied by later radio observations. The star actually gets heated up and ionized, before being overtaken by the expanding cloud of stellar matter.

Researchers say that this kind of phenomenon is generally found in a relatively standard type II supernova. They also believe that the type of instability the stars show is more like a warm up before the core collapse, leading to the ultimate explosion.

To come to this precise conclusion, the researchers had to go through unique dataset collected from the first days of observing a supernova. The results of the research were published in the journal "Nature Physics".