Published 21:48 IST, January 15th 2021
'How old are supernovas?': NASA astronomers rewind clock to estimate star explosion age
“The victim is a star that exploded long ago in Small Magellanic Cloud, a satellite galaxy to our Milky Way," NASA astronomers studying supernova's age said.
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Researchers at NASA are rewinding the clock to calculate the age of the Supernova blast. NASA's Hubble Space Telescope captured an explosion of a nearby star, scientists are now trying to calculate an accurate estimate of the location and time of the stellar detonation. According to a release by NASA, “The victim is a star that exploded long ago in the Small Magellanic Cloud, a satellite galaxy to our Milky Way.” Moreover, after the explosion, the dying star left behind an expanding, gaseous corpse, a supernova remnant named 1E 0102.2-7219, which was observed by NASA's Einstein Observatory first discovered in X-rays.
Scientists at NASA are now studying the archival images captured by Hubble and are analyzing the rare visible-light observations which were made by astronomers 10 years apart. In order to find the accurate explosion age, a research team, led by John Banovetz and Danny Milisavljevic of Purdue University in West Lafayette, Indiana, studied the velocities of 45 tadpole-shaped, oxygen-rich clumps of ‘ejecta’ flung by the supernova blast. According to NASA, the “ionized oxygen is an excellent tracer because it glows brightest in visible light.” Astronomers observed at least 22 fastest moving ejecta clumps that travelled through interstellar material to determine the accurate age of the supernova explosion. They also studied the backward motion of the ejecta until it coalesced to identify the explosion’s accurate site.
Calculated speed of neutron star
“Light from the blast arrived at Earth 1,700 years ago, during the decline of the Roman Empire. However, the supernova would only have been visible to inhabitants of Earth's southern hemisphere,” NASA said in the release. However, the individual research indicated that each of these phenomena occurred between 2,000 and 1,000 years ago. "A prior study compared images were taken years apart with two different cameras on Hubble, the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys (ACS),” scientist Milisavljevic said. "But our study compares data were taken with the same camera, the ACS, making the comparison much more robust; the knots were much easier to track using the same instrument,” he added.
Furthermore, using Hubble, astronomers calculated the speed of the suspected neutron star, moving at more than 2 million miles per hour from the center of the explosion. "That is pretty fast and at the extreme end of how fast we think a neutron star can be moving, even if it got a kick from the supernova explosion," Banovetz said. "More recent investigations call into question whether the object is actually the surviving neutron star of the supernova explosion,” he added.
(Image Credit: NASA)
21:48 IST, January 15th 2021