NASA Spies a Supernova’s First Shockwave
Astronomers spot the first flash of a distant supernova in visible light
When a dying star explodes into a supernova, it can produce a short shockwave known as a “shock breakout.” Now, for the first time astronomers have caught a glimpse of the first flash of a supernova in visible light thanks to the Kepler telescope.
Supernovas tend to occur when an aging red giant star has expended the last of its nuclear fuel. Because the star can’t sustain itself any longer, it collapses before exploding in a massive burst of energy. But while supernovas can last weeks at a time, the initial shock breakout is quick, lasting only about 20 minutes, which makes them difficult to capture, Michael Slezak reports for The Guardian.
“We’ve always thought that this is the physical mechanism that allows the star to blow up,” Brad Tucker, an astrophysicist at the Australian National University, tells Slezak. “It’s been this fundamental thing that we’ve always thought occurs but we’ve never seen it take place.”
In the past, astronomers have observed shock breakouts with x-ray telescopes, but never in as great detail as the Kepler telescope’s most recent finding, which was captured in the visible light spectrum. According to new research published in Astrophysical Journal, a team of researchers at Indiana’s University of Notre Dame have been combing through reams of data gathered by the space telescope dating back years. The supernova in question, as illustrated in an artist’s animation above, actually occurred in 2011 and was just one of about 50 trillion stars that the Kepler telescope can observe at one time, Jamie Condliffe reports for Gizmodo.
“In order to see something that happens on timescales of minutes, like a shock breakout, you want to have a camera continuously monitoring the sky,” astrophysicist Peter Garnavich, who led the research, says in a statement. “You don’t know when a supernova is going to go off, and Kepler's vigilance allowed us to be a witness as the explosion began.”
Astronomy usually operates on a timescale measured in millennia, making a minutes-long event like this a rare find. Yet some mystery still surrounds this exciting event. A second, similar supernova exploded around the same time, but the telescope didn’t catch a shock breakout in that case, Slezak reports. Most astronomers believe that shock breakouts are the events that trigger the cataclysmic supernovas, and researchers are still trying to figure out why the Kepler recorded one, but not the other.
“That is the puzzle of these results,” Garnavich says in a statement. “You look at two supernovae and see two different things. That’s maximum diversity.”
Right now, scientists believe that the supernova with the missing shockwave may have been obscured by gas surrounding the dying star, or that it may have been too weak for the telescope to pick up. But as many continue to puzzle over the mystery, scientists will continue combing the skies for new supernovae in hopes that they can teach us more about our own little planet, Mary Beth Griggs reports for Popular Science.
"All heavy elements in the universe come from supernova explosions. For example, all the silver, nickel, and copper in the earth and even in our bodies came from the explosive death throes of stars," NASA scientist Steve Howell says in a statement. "Life exists because of supernovae."