This Hubble image shows Eta Carinae, a double star system 7500 light-years away, which has been exploding in slow motion for more than a hundred and eighty years.
The system contains at least two stars which glow five million times brighter than our Sun, and the dramatic event began in 1838, when it experienced an enormous explosion called the Great Eruption. The event threw off enough light that it became the second brightest in the sky by April 1844, and sailors and mariners in the southern seas used it for navigation. It almost destroyed the system, but the light eventually faded although the explosions continued.
A smaller eruption happened in 1892, and it has grown consistently brighter since 1940, suggesting the activity is still ongoing. This video traces the evolution of this remarkable system:
The new image from Hubble has revealed more information about the two round globe shapes formed by dust, gas, and other materials pushed out into space by the explosion. It was previously thought that the clouds would glow with magnesium illuminated by nitrogen (which is shown in red in the image), but in fact complex magnesium structures were found in between the bubbles of gas instead.
“We’ve discovered a large amount of warm gas that was ejected in the Great Eruption but hasn’t yet collided with the other material surrounding Eta Carinae,” Nathan Smith of Steward Observatory at the University of Arizona, lead investigator of the Hubble program, explained in a statement. “Most of the emission is located where we expected to find an empty cavity. This extra material is fast, and it ‘ups the ante’ in terms of the total energy of an already powerful stellar blast.”
Hubble captured ultraviolet wavelengths of light to create the image, which help to illuminate warm gas is a different way from other wavelengths.
“We had used Hubble for decades to study Eta Carinae in visible and infrared light, and we thought we had a pretty full account of its ejected debris. But this new ultraviolet-light image looks astonishingly different, revealing gas we did not see in either visible-light or infrared images,” Smith said. “We’re excited by the prospect that this type of ultraviolet magnesium emission may also expose previously hidden gas in other types of objects that eject material, such as protostars or other dying stars; and only Hubble can take these kinds of pictures.”
