The discovery of a Wolf-Rayet supernova rebuts the idea that the biggest stars go quietly.
A long time ago, a faraway star threw up its insides and ended its days in a colossal explosion. The first light to hold the record of this supernova reached Earth about this time last year. Just a few hours later, quick-thinking astronomers were able to point a telescope at the hole in the sky where the star had been. The resulting images help to resolve a key question in stellar physics. And they might raise more questions about the fate of Earth.
Supernovae are one of the most stunning events in the night sky; the explosions are so well known for their violence that the term has even entered common parlance. Yet supernovae are rare, and so, therefore, are direct observations of the circumstances immediately before and after them.
As astronomers describe on page 471 of this issue, being able to focus on the immediate aftermath of a supernova has shed new light on why some stars go bang with such force. In this case, the emissions spectra sent out by the dying star show that it was a Wolf–Rayet star, massive bodies that shed their mass rapidly in strong stellar winds.
The finding is significant because, although astronomers assumed that Wolf–Rayet stars would go supernova, there was no direct evidence that they did. In fact, in the absence of observations of such supernovae, a rival theory was gaining ground: that they might end their lives not in a bang but with a whimper. As John Eldridge explains in an accompanying News & Views article on page 431: “Until this event, there was growing evidence that such stars were likely to have dim or unobservable deaths.”
Written By: Nature
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