Supernova SN 2019ehk exploded in galaxy M100 55 million light years away last spring. Remarkably, amateur astronomer Joel Shepherd discovered this, but the Hubble Space Telescope saw nothing. This is not without reason – SN 2019ehk belongs to the unique objects that are responsible for the creation of more than half of all calcium in the universe, including the one in our teeth.
After a year of studying SN 2019ehk and its legacy, scientists called this generation of calcium the most powerful in history. Stars usually produce very little of this element by slowly burning off helium over the course of their existence. But in supernovae everything happens differently, and in the case of SN 2019ehk, the explosion led to the collision of the star’s matter with the outer ring of gas, which generated enormous temperature and pressure. This triggered a nuclear reaction, which led to the synthesis of an exorbitant amount of calcium.
The incident was so rare and surprising that less than 10 hours after the discovery of the supernova, the world’s best telescopes were already tracking it. And just in time, because the scientists managed to fix X-rays of unprecedented brightness, which disappeared after five days. Because of such rates of the processes, it is not always possible to notice such cases, which gave rise to contradictions regarding the origin of “stellar” calcium.
It is noteworthy that over 25 years of observations, Hubble repeatedly looked into the galaxy M100, but found nothing there. He also did not see a supernova, from which it was concluded that SN 2019ehk is a dim and light star or a white dwarf. And it is objects of this type, not huge stars, that are responsible for the origin of most of the calcium in the universe.