Decoding the Mystery behind Disappearance of a Star in Andromeda Galaxy

Abstract

Recently it has been reported by a researching team from the MIT that a supergiant star M31-2014-DS1 having mass of 20 times the sun has disappeared in the Andromeda galaxy. The star had failed to explode as a supernova and had become directly a black hole. Normally, as per the present theory, when core of a massive (more than 8 times solar mass) star of this type collapses, the final event is accompanied by bursts of light brought on by stellar explosion known as supernova. In this particular instance, the researchers could not get any trace of optical outburst during the last phase of the dying supergiant star and reported direct formation of a black hole. This phenomenon is being hyped as a mystery by the astronomers.  

However, it has also been observed by the researchers that though the star was born with an initial mass of about 20 solar mass, it had reached its terminal nuclear burning stage at about 6.7 solar mass. In this article it has been mathematically established that a giant star of mass less than 7.15 times the solar mass cannot explode as supernova; rather it will become a black hole. Therefore, a star of 6.7 times the solar mass will logically end up in a black hole and finally will be settled as a black hole-cum-neutron star, without exploding as supernova. It has also been proved theoretically that if the star would have a mass of 20 solar mass, it would have exploded as supernova. Therefore, the calculations confirm that there is no mystery behind the disappearance of the said star and formation of a black hole in the Andromeda galaxy.