Astronomers have discovered the strongest stellar explosion we have ever observed
The article describes an explosion called SN2016aps, which is 500 times brighter than a typical supernova explosion. Astronomers call its explosion rare in the universe, but it is debatable what type of explosion it types.
Illustration: SN 1994D (bright spot in the lower left), a type IA supernova located in its host galaxy NGC 4526
Image source: wikipedia
Massive stars don't die quietly. Their demise is a spectacular explosion that can eclipse the entire galaxy. And now, astronomers have identified the strongest exploding star we've ever seen.
The supernova, named SN2016aps, was observed on February 22, 2016, by a transient observation of the Panstal Survey on a galaxy 4.5 billion light-years from Earth.
Illustration: This is the pan-STARRS logo. More details: Pan-STARRS logo designed by Malia Wisch in May 2005.
Now, astronomers have determined that SN2016aps are 500 times brighter than a typical supernova explosion. They say it's the brightest, most vibrant, and perhaps even biggest supernova we've ever seen — pushing it into the category of supernovae.
"The explosion of SN2016aps was spectacular in many ways," explains Edo Berger, an astronomer from Harvard University. "Not only is it brighter than other supernovae we've ever seen, but it has so many properties and features that make it rarer than the explosions of other stars in the universe."
Illustration: NASA artist's impression of the explosion of the super-bright supernova SN2006gy
Although SN2016aps reached its peak in January 2016, observations of it were not limited to that time. When supernovae were discovered in the Pinstal data, astronomers have been carefully observing how objects darken over time, a process that is still happening.
They also looked at data obtained before the January 2016 peak and saw that SN2016aps had been glowing for weeks before the Big Bang, dating back to December 2015.
The total kinetic energy of SN2016aps is about 5x1052erg, comparable to the famous 1998 supernova SN1998bw, which was 25 times the weight of the predecessor star to 40 times the weight of the Sun. But the peak brightness of SN2016aps is 4.3x1044erg, which is 1x1043-erg brighter than the peak brightness of the 1998bw supernova.
"The intense energy output of this supernova points to an ancestor of stars of astonishing mass," Berg said. "Since its inception, this star has weighed at least 100 times as much as the Sun."
Still, it's impossible for the star itself to produce such a massive explosion. In fact, as the spectral observations of this supernova reveal, it does have some peculiarities.
illustrate:
An example of spectroscopy: a prism analyzes white light by dispersing it into its constituent colors.
"We determined that in the last few years before it exploded, as it shook violently, the star shed a massive gas shell," said Matt Nicole, an astronomer at the University of Birmingham. "The collision of the explosive wreckage with this massive shell resulted in the incredible brightness of the supernova. It essentially added fuel to the explosion. ”
While it is normal for a dying star to decline in mass, it is unusual for a star to drop so much mass in such a short period of time as it is from its explosion. Research into how and why this phenomenon occurs needs to be done through simulation experiments and modeling.
The researchers also found high levels of hydrogen, which is puzzling because massive stars typically disperse most of the hydrogen before forming supernovae. But the puzzle has one answer: The big star was once formed by the merger of two small stars.
"SN2016aps was able to hold its hydrogen, which led us to infer that two less massive stars had merged because the less massive stars held hydrogen longer." Berg said.
The mass and abundance of hydrogen in this pre-merger star could make SN2016aps a rare type of supernovae that can only be seen in supermassive stars rich in hydrogen and helium, called pulse pair instability supernovae.
It's an event that looks like a very bright supernova, but only a portion of the star's mass is blown into space, leaving a less massive star that will eventually experience a true supernova.
A low probability, but still a possibility, is an all-pair instability supernova. This means that when the core of a massive star is very hot, it produces electron-positron pairs, which reduces the radiation pressure that prevents the star from disintegrating. This can lead to a runaway nuclear explosion that completely blows the star apart without even leaving a remnant of the core.
Illustration: When a star is massive, the gamma rays produced by its core become so energetic that some of their energy is lost to the production of particle and antiparticle pairs. The resulting drop in radiation pressure causes the star to partially collapse under its own enormous gravitational pull. After this violent collapse, an out-of-control thermonuclear reaction (not shown here) followed, and the star exploded. Image source: wikipedia
We still don't know which of these SN2016aps is. Detailed simulation experiments are needed to help solve this problem.
But now that SN2016aps has been confirmed, we will be able to explore more similar events. This can also help us paint these incredible explosions.
"The identification of SN2016aps opens the way for identifying similar events from first-generation stars." Berg said.
"With the advent of the upcoming large weather observation telescope, we can detect such an explosion from the first billion years of cosmic history, when there will be a large number of examples."
Illustration: Vera C. Rubin Observatory, formerly known as the Large Integrated Survey Telescope (LSST), is an astronomical observatory in Chile currently under construction. Image source: wikipedia
The study was published in Natural Astronomy.
BY: MICHELLE STARR
FY: Zhang Yutu
If there is any infringement of the relevant content, please contact the author to delete it after the work is published
Please also obtain authorization to reprint, and pay attention to maintaining completeness and indicating source