Calcium-rich supernova examined with X-rays for first time

Calcium-rich supernova examined with X-rays for first time

Half of all the calcium in the universe—including the very calcium in our teeth and bones—was created in the last gasp of dying stars. Called "calcium-rich supernovae," these stellar explosions are so rare that astrophysicists have struggled to find and subsequently study them. The nature of these supernovae and their mechanism for creating calcium, therefore, have remained elusive. Now a Northwestern University-led team has potentially uncovered the true nature of these rare, mysterious events. For the first time ever, the researchers examined a calcium-rich supernova with X-ray imaging, which provided an unprecedented glimpse into the star during the last month of its life and ultimate explosion. The new findings revealed that a calcium-rich supernova is a compact star that sheds an outer layer of gas during the final stages of its life. When the star explodes, its matter collides with the loose material in that outer shell, emitting bright X-rays. The overall explosion causes intensely hot temperatures and high pressure, driving a chemical reaction that produces calcium. "These events are so few in number that we have never known what produced calcium-rich supernova," said Wynn Jacobson-Galan, a first-year Northwestern graduate student who led the study. "By observing what this star did in its final month before it reached its critical, tumultuous end, we peered into a place previously unexplored, opening new avenues of study within transient science." "Before this event, we had indirect information about what calcium-rich supernovae might or might not be," said Northwestern's Raffaella Margutti, a senior author of the ...
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