What are Some Different Types of Supernovae?

A supernova burst is a violent explosion that some stars experience as they approach the end of their evolution. These explosions are extremely bright, and the sudden electromagnetic radiation in the process can often illuminate the entire galaxy in which it is located, and it can gradually decay for a few weeks to several months to become invisible. During this period, the energy radiated by a supernova is comparable to the sum of the energy radiated by the sun in its lifetime ^[1] . A star explodes and disperses most or almost all of its material at speeds as high as one-tenth the speed of light ^[2] and radiates shock waves to surrounding interstellar matter ^[3] . This shock wave results in the formation of a shell-like structure of expanding gas and dust, which is called a supernova remnant. Supernovas are a potentially powerful source of galaxy gravitational waves ^[4] . A large proportion of primary cosmic rays come from supernovas ^[5] .

The earliest supernova record was SN 185, seen by Chinese astronomers in AD185. The brightest supernova in the record is SN 1006, which is well documented by Chinese and Islamic astronomers. ^[7]

On December 7, 185, in the second year of the Eastern Han Dynasty, Chinese astronomers observed the supernova 185, the first supernova discovered in human history. ^[12]

The classification code given to supernovas by astronomers is a very natural classification: the value given to the type of light observed from a supernova is not necessarily the cause. For example, the ancestral star of the supernova Ia is a degenerate white dwarf, resulting from uncontrolled ignition; the ancestral star of an Ib / c supernova with a similar spectral type is a massive Wolf-Rayet star ignited by core collapse. The following summarizes what astronomers currently think is the most reasonable explanation for a supernova. ,

The most recent observation of the Milky Way supernova was the Kepler Star of 1604 (SN 1604); retrospective analysis has found two newer remains ^[30]

According to China National Astronomy magazine, an international team led by Dong Subo, a researcher at the Thousands of Young People at the Institute of Astronomy and Astrophysics at Peking University, discovered a supernova.

This latest research result was discovered in the summer of 2015, and was subsequently published in Science on January 15, 2016, with East Sub as first author and corresponding author. The article introduces that ASASSN-15lh is 3.8 billion light-years away from Earth, and is a member of the rare "extremely bright supernova" family. Its discovery is expected to provide important clues for astronomers to unravel the mystery of extremely bright supernovae.

China National Astronomy claims that supernova is a violent burst of stars at the end of life. Nearly two thousand years ago, Chinese astronomers recorded the earliest supernova outbreaks in the history of mankind in the "Han Han Book". The supernova, now known as SN 185, was classified as type Ia by astronomers. Since then, humans have recorded tens of thousands of supernova explosions, the most common of which is type Ia. And a supernova discovered in the summer of 2015 shocked the astronomy community-its burst intensity was about two hundred times greater than that of a type Ia supernova, more than twice the current record holder.

The highest luminosity reached by ASASSN-15lh is 570 billion times stronger than the sun, which is about 20 times the total luminosity of the entire galaxy's 100 billion stars. East Subbot said in the research results: "ASASSN-15lh is by far the strongest supernova explosion recorded by human beings. Because its radiated energy is too high, the current supernova theory is difficult to give its explosive mechanism and energy source. Satisfactory explanation. "

ASASSN-15lh was discovered in June 2015 by two 14 cm telescopes. On the day of ASASSN-15h's discovery, East Sub and its collaborators immediately disclosed the relevant information to supernova researchers around the world, so that people can make observations faster and better. ASASSN-15lh aroused strong interest from astronomers. Many large telescopes in the world and NASA's "Swift" space telescope immediately began follow-up observations. To this day, researchers are still observing this supernova in many bands from optics to X-rays to radio.

After discussing with colleagues, Professor Jose Prieit (University of Diego Diares, Chile) and Professor Steinick, East Sub was suddenly aware that ASASSN-15lh might belong to the super bright supernova. According to his speculation, if ASASSN-15lh is 3.8 billion light-years away from us, its most prominent spectral line characteristics closely match the spectrum of an extremely bright supernova discovered in 2010. If this inference is correct, you should be able to see the absorption lines of supernova light passing through the gas in the host galaxy at specific wavelengths. The expected characteristic absorption line has a short wavelength, and it needs to be observed with an instrument that covers enough blue-end spectrum. In the next few days, East Sub and his colleagues contacted three telescopes that could capture the blue-end spectrum. Unfortunately, several observations failed due to weather and instrument failure. Ten days later, the 10-meter "South Africa Giant Telescope" (SALT) finally successfully captured the required spectrum, and East Subb's inference was confirmed.

"National Astronomy of China" states that at 2 am Beijing time on July 1, 2015, East Sub received the observation information from the South African telescope. "When I saw the spectrum taken by the South African telescope and realized that we had discovered the strongest supernova outbreak in history, I was so sleepy."

East Sub was selected in the Thousand Talents Program (Youth Project) of the Organization Department in 2014. He is also a core member of the Chinese Academy of Sciences' Strategic Origin Program for the Origin of the Universe Structure. This strategic pilot project led by the National Astronomical Observatory has created a comprehensive observation network of advanced telescopes at home and abroad, focusing on cultivating developments and breakthroughs in many scientific frontiers, including time-domain astronomy. The discovery of this extreme supernova is also a fruit of Chinese scientists in the field of time domain astronomy.

The astronomy community believes that supernova is at the intersection of many different branches of astronomy research. As the final destination of many kinds of star life, supernova can be used to test the current theory of stellar evolution. ^[37]