Type la supernova are one of the most violent explosions in the universe. But what makes them so special is that they make a very specific glow due to the physical mechanism that gives birth to it. It is not wrong to say that cosmology is one of the pupils, since their mere brightness is known and they can be seen from far away. But there is still quite a lot of debate about their rights.
Type Ia supernova occur in double star systems. Most stars in the universe exist in binary systems. If their mass is different from each other, which is quite possible, one of the pairs evolved early, realizing a planetary nebula, leaving behind a white dwarf. Because white dwarfs are quite cramped bodies, you can’t easily disrupt their structure, but that’s not the case for the component next to it. No matter what kind of Star the other component is, the white dwarf begins to steal matter from that star, but it cannot continue to do so forever.
A white dwarf (WD) consisting of carbon and oxygen, as it steals mass from its component, its mass approaches 1.38 m⊙ (Chandrasekhar’s mass), causing the sudden onset of a high-temperature nuclear fusion reaction*. These reactions, which start suddenly in the white dwarf, suddenly cause the white dwarf to explode violently without leaving any residue. The medium energy is enormous (1051 erg or 1031 megatons), which means that it releases roughly all of the energy emitted by the sun during its lifetime at once. Most of this release is not in the visible (optical) region, and a significant part is also carried through neutrinos.
Significance In Cosmology
The reason Type Ia supernovae (written as Type Ia SNe) are so important in cosmology is that they are considered standard candles. The fact that there is an event at a significant mass value that always happens in the same way says that they should give the same pure brightness wherever it occurs. In astronomy, if you know the mere brightness of an object, it is possible to determine its distance by using its apparent brightness. At the same time, because they are extremely bright, they can appear from very long distances. For this reason, they are used in cosmological distance measurements and provide information about the dynamic development of the universe over time.
In 1998, Riess, Schmidt, and Perlmutter (and Others) ‘ s work on Type Ia supernovae showed that the universe is expanding by accelerating and that a dark energy must exist. They were awarded the Nobel Prize in 2011 for their work. Their work was roughly to study the variation of the Hubble constant with distance. They were actually studying the change of the Hubble constant over time, because the further you look, the more you will see the past. Their findings showed that it was not a linear relationship, as Hubble had put it in 1929, but that the constant was a parameter that changed over time. Of course, such a situation had a profound effect. This issue is still highly controversial, and a significant number of cosmologists claim that the data has been misinterpreted for some reason. Last year, Subir Sarkar of Oxford applied a different method of statistical analysis with more data, claiming that there was no acceleration, which caused a deep debate.
For this reason, it is still quite controversial whether Type Ia supernovae can be considered standard candles today. I can’t pass without mentioning, observing very distant points is always open to discussion. Because there are also theories that claim that some universal constants must change over time, and if one of them is true, it could explain this strangeness observed in supernovae and completely throw away the idea of dark energy. In a nutshell, this topic is still a fairly hot and current topic.
- Here it is often confused with Chandrasekhar mass, Chandrasekhar limit. The Chandrasekhar limit is the mass limit where degenerate electron pressure cannot prevent inevitable collapse. Its generally accepted value is 1.4 M⊙(1.4 solar mass).
- Mazzali, P. A., Röpke, F. K., Benetti, P., & Hillebrandt, W. (2007). A common explosion mechanism for Type Ia supernovae. Science (New York, N.Y.), 315(5813), 825–8. https://doi.org / 10.1126 / science.1136259
- Nielsen, J.. T., Guffanti, A., & Sarkar, P. (2016). Marginal evidence for cosmic acceleration from Type Ia supernovae. Scientific Reports, 6 (1), 35596. https://doi.org / 10.1038/srep35596
- Riess, A. G., Filippenko, A. V., Challis, P., Clocchiatti, A., Diercks, A., Garnavich, P. M., Tonry, J. (1998). Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant. The Astronomical Journal, 116 (3), 1009-1038. https://doi.org / 10.1086 / 300499
- NASA, Introduction to Supernova Remnants,