A star survives a supernova
Wonder for a team of astronomers on the site of the thermonuclear supernova SN 2012Z: a Hubble telescope discovers a star that survived its explosion.
A team of astronomers went to browse the site of the thermonuclear supernova SN 2012Z , being literally speechless. Thanks to a Hubble telescope they discovered that a star had survived its explosion . And this is not the only surprising fact. Yes, because the star shone even more than before, after the supernova. The name of these thermonuclear supernovae is supernova la . Furthermore, they are among the most important instruments in the hands of astronomers to measure the distances of the cosmos.
Since 1998 it has been found that the universe is growing faster and faster. And what is the cause of this responsibility? Well, to dark energy. The discovery of this energy was awarded the Nobel Prize in Physics in 2011.
For astronomy, thermonuclear supernovae are essential, although they are still poorly understood. It seems to scholars that this is the explosion of white dwarfs . The latter are stars made up of the mass of the Sun, but are located inside the Earth. The reason for their destruction is still unknown. It seems that the white dwarf steals matter from its companion star. When it gets too heavy, then it triggers reactions that lead to an explosion that causes the star to die out of control.
The thermonuclear supernova SN 2012Z is a particular type also called the lax type . It is related to that of type la . For scientists they are considered failed supernovae of type la . The sighting of the supernova 2012Z had already been detected in 2012 near the spiral galaxy NGC 1309. The Hubble telescope had taken images in 2013, comparing which star from old photos could match the one that exploded. In 2014, in fact, scientists were able to identify it in the supernova 2012Z. This episode corresponds with the first identification of the progenitor star of a white dwarf supernova.
Curtis McCully, researcher with UC Santa Barbara and the Las Cumbres Observatory, exposed these findings at a press conference. They are findings that show news about the mysterious origins of some common explosions in the universe. Here are his words:
We expected to see one of two things when we got the most recent Hubble data. Either that the star would have disappeared completely, or perhaps it would still be there, which would have meant that the star we identified in the pre-blast images was not the one that exploded. No one expected to see a brighter surviving star. It was a real puzzle.
The study team and McCully consider the hypothesis that the semi-exploded star became brighter due to the bulge assumed in a larger star. The supernova was unable to eliminate all the material, and the latter fell back into a so-called bonded remnant. Scientists expect that over time the star will be able to resume the state it had in the beginning. Although with less mass and greater size. As the mass decreases, the diameter of the white dwarfs increases.
This surviving star is a bit like Obi-Wan Kenobi returning as a force ghost in Star Wars. Nature tried to bring this star down, but it came back more powerful than we could imagine. It is still the same star, but it comes back in a different form. He has transcended death.
Andy Howell, professor at UC Santa Barbara and senior scientist at the Las Cumbres Observatory
Scientists have long believed that the A-type supernova explosion could occur when a white dwarf star reached a certain size limit . The latter is called Chandrasekhar , and is approximately 1.4 times the mass of the Sun. However, this theory has recently collapsed as several supernovae have appeared with less mass than this. New theories have hypothesized other factors that cause them to be destroyed. Astronomers have never been sure that these stars, before the explosion, have ever approached the so-called Chandrasekhar limit .
Now the study team thinks that this growth, up to the last limit, is equal to what happened to the thermonuclear supernova SN 2012Z.
The implications for Type Ia supernovae are profound. We have found that at least supernovae can grow to the limit and explode. Yet the explosions are weak, at least sometimes. Now we need to understand what makes a supernova fail and become a Type Iax, and what makes a supernova successful as Type Ia.
Curtis McCully, researcher at UC Santa Barbara and the Las Cumbres Observatory
- The star that survived a supernova (reccom.org)