14 DAY TRIAL // Astronomers propose a new theory related to the core of very large stars. They say that, when the inner parts of such a celestial body become too hot, they start forming matter-antimatter pairs. Naturally, when this happens, the basic laws of physics dictate that a violent annihilation between the two occurs, and this is seen on the outside as a massive explosion. To back up their new idea, the experts showcased the example of the distant star Y-155, which exploded around seven billion years ago, when the entire Universe was about half its current age.
At the beginning, models show, Y-155 was most likely about 200 times more massive than the Sun. However, as it grew, it became so hot that it entered a phase astrophysicists called “pair-unstable.” As the name implies, no star can resist in this configuration for long, so the celestial body exploded. This took place with such force, that the light from the explosion became visible halfway around the Universe. At the basis of the strong detonation was a runaway thermonuclear reaction, physicists believe. The work was led by researchers at the University of Notre Dame, led by expert, astronomer Peter Garnavich.
“In our images, Y-155 appeared a million times fainter than the unaided human eye can detect, but that is because of its enormous distance. If Y-155 had exploded in the Milky Way it would have knocked our socks off,” the astronomer said yesterday. He was speaking in Washington DC, at the 215th meeting of the American Astronomical Society (AAS). The star can be found in the constellation Cetus. The research team used the four-meter Blanco telescope in Chile for the observations. The instrument belongs to the National Optical Astronomy Observatory (NOAO).
The stellar remnant was just one of the 200 weaker stellar explosions that were identified during the six-year “ESSENCE” supernova survey. “ESSENCE found many explosions in our 6 years of searching, but Y-155 stood out as the most powerful and unusual of all our discoveries,” Garnavich said at the meeting. He added that the goal of the project was to collect more data on the elusive dark energy, which is thought to be driving the expansion of the Cosmos. The work was conducted with funds from the US National Science Foundation (NSF).