No. 76

June 2011

Headline News Innovation and Development

Applied Technology

Basic Science Cooperation between CAS and Local Authorities
Bioscience International Cooperation Brief News Geoscience

Basic Science

New Achievement on Ia-type Supernova Explosion

On Apr. 26th, U.S. Chandra X-ray Observatory Science Center released a piece of news titled NASA's Chandra Finds New Evidence on Origin of Supernovas, which reported the results of a research on Ia-type supernova explosion completed based on the observational data of U.S. Chandra X-ray Observatory through the cooperation with CAS¡¯s Institute of High Energy Physics, U.S. University of Massachusetts, and the Xiangtan University. Lu Fangjun from the Institute of High Energy Physics cooperated with Q. Daniel Wang from the Department of Astronomy of the University of Massachusetts and found a special X-ray arc in Tycho¡¯s supernova remnant after an analysis of Chandra X-ray Observatory¡¯s observational data of this remnant. They compared this result with the observational results of other wavelengths and found that this arc possibly originated from the companion star¡¯s outer envelope being stripped in the supernova explosion. Out of the arc, there still exists an area lacking the explosive projectiles of the white dwarf, which rightly corresponds to the obstruction and deceleration of companion stars to explosive projectiles. These images were ever forecasted by a large number of theories and numerical simulation research on Ia-type supernovas, but this is the first observational evidence. According to the location of X-ray arc and earlier observations of companion star candidates, Lu Fangjun and other researchers further inferred that the progenitor star of Tycho¡¯s supernova has a binary star orbital period of about five days and a radius around 10 million km, and that the companion star was stripped off the outer gas of approximately 2/1000 of the solar mass in explosion and obtained the acceleration around 40km/s at the same time. The results were published on May 1st issue of the Astrophysical Journal.

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