Aldana Grichener, who is now publishing her first scientific article, began studying at the Technion in the Rothschild Scholars Technion Excellence Program around 18 months ago.
Grichener, 21, was born in Argentina and immigrated to Israel with her family as a baby. She was accepted into the MOFET (mathematics, physics and community culture) program at Makif Zayin comprehensive high school in Ashdod, and at the early age of 15 she decided to attend the Technion, “because scientific research attracted me and I knew that the Technion is the best place for it.” Three days after her discharge from the IDF she began her studies at the Technion, and in her first semester she attended a course taught by Prof. Noam Soker from the Faculty of Physics. “I liked his attitude as a lecturer and as a person – he does everything for his students and is always willing to talk to them outside office hours. I read his articles and thought it would be interesting to work with him, so I approached him and asked him to be my undergraduate project advisor.” Prof. Soker assented to her request, which has led to an article that will soon be published in the journal Monthly Notices of the Royal Astronomical Society. The topic: a new model for the formation of the “Mickey Mouse ears” that characterize many supernova remnants.
Supernova is a phenomenon typical of heavy stars at the end of their lives. This process begins with the collapse of the star into itself, an event in which the radius of the inner part known as the core shrinks, becoming a thousand times smaller. In this process, in which the inside of the star shrinks to a diameter of about 20 km, a neutron star of enormous density is created: one billion tons per cubic centimeter. The shrinking, which is the result of gravitational force, is stopped at some point and replaced by a huge explosion that expels the star’s outer shell – the parts that remained during the shrinking process – at a speed of millions of km per hour.
“When we study the morphology of supernova remnants, we find that a third of them have two ‘ears’ protruding from the main body. The usual explanation for supernova explosions fails to explain the ear phenomenon, and in this paper we propose an alternative model consistent with various simulations, observations and calculations.”
According to Grichener’s and Prof. Soker’s model, the ears are formed by the emission of jets launched during the explosion of a star or shortly afterward. These gas jets are emitted as a result of the rapid rotation of the core that precedes the collapse, and they carry an enormous quantity of kinetic energy. “On the way, these jets encounter exploding gas, and this encounter inflates the ears that we see. Therefore, we claim that a paradigm shift should be made in the explanation of the explosion of heavy stars, known as the core-collapse supernova.