A new study of nearby supernova SN 1987A answers a long-standing debate.
A new method to measure the atomic temperature during the death of a star explosion will help scientists understand the shock wave produced by a supernova explosion. The research of an international research team, including scientists from Pennsylvania State University, combines the observation of nearby supernova remnants-the structure left by the explosion of stars, and the simulation of heated substances to measure gas atoms around low-temperature stars.
The research team used the Chandra X-ray Observatory of NASA to analyze the long-term observation results of nearby supernova remnant SN 1987A, and established a model to describe supernova. The research team confirmed that even the temperature of the heaviest atoms-which has not been studied yet-is related to their atomic weights, which answered a long-standing question about shock waves and provided important information about their physical processes. The paper describing this result was published in Journal of Natural Astronomy 20191KLOC-0/October 265438.
"Supernova explosions and their debris provide us with a cosmic laboratory, which enables us to explore physics under extreme conditions that cannot be replicated on Earth," said David bruns, a professor of astronomy and astrophysics at Pennsylvania State University and one of the authors of the paper. "Modern astronomical telescopes and instruments, both on the ground and in space, enable us to conduct detailed research on supernova remnants of the Milky Way and nearby galaxies. We used the Chandra X-ray Observatory of NASA to make routine observations on the supernova remnant SN 1987A. Chandra X-ray Observatory is the best X-ray telescope in the world. Shortly after the launch of Chandra Telescope 1999, we answered the long-term question about shock wave by simulation.
The explosive death of a massive star like SN 1987A pushes matter outward at a speed as high as one tenth of the speed of light, pushing shock waves into the surrounding interstellar gas. Researchers are particularly interested in the shock front, that is, the sudden change between supersonic explosion and relatively slow moving gas around the star. The front of the shock wave heats this slow-moving cryogenic gas to millions of degrees-enough temperature for the gas to emit X-rays that can be detected from the earth.
Bruns said: "This change is similar to the phenomenon observed in the kitchen sink. When the high-speed water stream hits the sink, it flows smoothly outward until it suddenly rises and becomes turbulent. " "In the earth's atmosphere, shock fronts are widely studied, and they occur in a very narrow area. But in space, the transformation of shock wave is gradual and may not affect all elemental atoms in the same way.
The research team led by Marco Miceli and Salvato Le Orlando of Palermo University measured the temperatures of different elements behind the shock front, which will improve the understanding of shock process physics. These temperatures are expected to be directly proportional to the atomic weight of elements, but it is difficult to measure them accurately. Previous studies have led to contradictory results about this relationship, and did not include heavy elements with high atomic weight. The research team turned to supernova SN 1987A to solve this problem.
Supernova SN 1987A is located in the nearby large magellanic cloud, which is the first supernova visible to the naked eye since the discovery of Kepler supernova 1604. It is also the first celestial body to be studied in detail with modern astronomical instruments. 1On February 23rd, 987, the light emitted by its explosion first reached the earth. Since then, people have observed various wavelengths of light, from radio waves to X-rays and gamma waves. The research team used these observations to build a model to describe supernovae.
Bruns said: "We can now accurately measure the temperatures of heavy elements such as silicon and iron, and it has been proved that they do follow the relationship that the temperature of each element is directly proportional to the atomic weight of that element." "This result solves an important problem in understanding astrophysical shock waves and improves our understanding of the shock wave process."