Star's shockwave captured on camera
[caption id="attachment_270624" align="alignleft" width="400"] Photo courtesy: NASA[/caption]Astronomers through NASA's Kepler space telescope have...
[caption id="attachment_270624" align="alignleft" width="400"] Photo courtesy: NASA[/caption]
Astronomers through NASA's Kepler space telescope have captured for the first time the flash of an exploding star’s shockwave or “shock breakout” in the optical wavelength or visible light.
The team of astronomers led by Peter Garnavich, astrophysics professor at the University of Notre Dame in Indiana, studied the light captured by Kepler every 30 minutes over a three-year period from 500 distant galaxies, closely watching upto 50 trillion stars.
The astronomers were hunting for supernovae, massive death explosion of stars.
For the first time, a supernova shockwave has been observed in the optical wavelength or visible light as it reaches the surface of the star.
This early flash of light is called a “shock breakout”.
The star named KSN 2011d reaches maximum brightness on exploding only after 14days, in order to be visible to the naked eyes.
In 2011, two of these massive stars, called red supergiants, exploded while in Kepler’s view. The first behemoth, KSN 2011a, is nearly 300 times the size of our sun and a mere 700 million light years from Earth. The second, KSN 2011d, is roughly 500 times the size of our sun and around 1.2 billion light years away.
“To put their size into perspective, Earth's orbit about our sun would fit comfortably within these colossal stars,” said Garnavich.
The shock breakout itself lasts only about 20 minutes, so catching the flash of energy is an investigative milestone for astronomers.
“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,” Garnavich added.
Supernovae like these also known as Type II - starts when the internal furnace of a star runs out of nuclear fuel at the core as gravity takes over.
The two supernovae matched up well with mathematical models of Type II explosions reinforcing existing theories. But they also revealed what could turn out to be an unexpected variety in the individual details of these cataclysmic stellar events.
Understanding the physics of these violent events allows scientists to better understand how the seeds of chemical complexity and life itself have been scattered in space and time in our Milky Way galaxy
"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," explained Steve Howell, project scientist for NASA's Kepler and K2 missions.
The research paper reporting this discovery has been accepted for publication in the Astrophysical Journal.
NASA has uploaded a video