Eta Carinae 'Light Echoes' Capture Glimpse of Eruption
Supermassive star Eta Carinae erupted over 170 years ago but scientists have captured "echoes" of the shockwave of light with a new technique.
Eta Carinae lies 7,500 light years from Earth. About 165 years ago, the southern star mysteriously became the second brightest star in the sky. The sudden lighting of the star is called the "Great Eruption."
The "light echo" technique allows scientists to see the eruption and shockwaves of light that bounced off clouds in space, enabling them to see the same moment that people did 170 years ago.
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The Eta Carinae has dimmed and lost an incredible amount of mass, but never died, leaving astronomers mystified. Today, the star is believed to be about 100 times the mass of our Sun.
Today, the star is moving toward the end of its life which will result in blast so violent, its flash will outshine the entire Milky Way.
"We know it's close to the end of its life," said astronomer Armin Rest of the Space Telescope Science Institute. Rest is the lead author of the report published in the latest edition of the science journal, Nature.
"It could explode in a thousand years, or it could happen tomorrow," continued the report.
Rest and his colleagues delved into the mysterious explosion of the Eta Carinae, and published their findings Thursday.
"With Eta Carinae, we are dealing with a really extreme phenomenon, which drags us into unexplored territory as far as theory is concerned," said Rest in the report.
The scientists at the Baltimore, M.D. based institute said that their findings suggest the Eta Carinae is not like other so-called "supernova impostors" and that the star was a lot colder than previously thought at the time of its brightening.
The findings also mean that researchers still do not know what caused the "Great Eruption" of the star.
"We do have some ideas- a collision between two stars in a binary system; an explosive but non-terminal thermonuclear burning event in the core of the star that might not release energy- but these are really just ideas and have no been very well-developed," Rest explained to Space.com.
"So we don't yet have clear predictions for the observed phenomena we expect to see," he added.
The scientists say they plan to look for more light echoes from the star to better understand the end-stages of very massive stars, and differentiate eruptions from supernova explosions.
