NASA/ESA Hubble Space Telescope has brought us a stunning view of Eta Carinae’s ongoing cosmic fireworks in ultraviolet light.
In the image above, you can see expanding gases glowing in red, white, and blue. The event is taking place about 7,500 light-years from Earth in the double star system Eta Carinae. It lies in the Carina or Ship’s Keel constellation.
Dust and gas forms the huge dumbbell shape in the image, as well as other filaments thrown by the explosion.
Astronomers call these hot glowing clouds the Homunculus Nebula, and Hubble has been observing them since its launch in 1990.
This is the highest resolution image of Eta Carinae that Hubble has ever taken.
The explosion took place in 1838 and the fireworks haven’t stopped since then.
Astronomers call this cataclysmic outburst the Great Eruption, which quickly grew in size. In 1844 it became the second brightest star in the sky. At the time, ships were using Eta Carinae to navigate the southern seas. The first brightest star was Sirius, a star a thousand times closer to us.
However, the star has faded since the eruption and is now barely visible to the unaided eye. But the spectacular display is still ongoing and Hubble Telescope has revealed details that no one has seen before.
Before the Great Eruption, Eta Carinae has experienced other chaotic eruptions in the past, blasting parts of itself into space.
Astronomers used Hubble’s Wide Field Camera 3 to map the ultraviolet-light glow of magnesium embedded in warm gas (shown in blue). But instead, they detected gas in places they had never seen it before.
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The outer material thrown off in the 1840s eruption has been heated by shock waves generated when it crashed into material previously ejected from the star. And scientists have long known about it.
The team had expected to find light from magnesium coming from the same array of filaments seen in the glowing nitrogen (shown in red) but they found a whole new luminous magnesium structure in the space between the dusty bipolar bubbles and the outer shock-heated nitrogen-rich filaments.
“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,” explained Nathan Smith of Steward Observatory at the University of Arizona, lead investigator of the Hubble programme. “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.”
The newly found data will help astronomers to better understand how the eruption began. But they will need more observations to measure how fast the material is moving and when did the ejection occur.
The streaks of light in the image appear much like sunbeams filtering through clouds or dust on Earth. Here, the star’s light is going through the dust and casting a shadow.
“The pattern of light and shadow is reminiscent of sunbeams that we see in our atmosphere when sunlight streams past the edge of a cloud, though the physical mechanism creating Eta Carinae’s light is different,” noted team member Jon Morse of BoldlyGo Institute in New York.
However, the final show will happen when the system explodes into a supernova that eclipses the Great Eruption. But no one knows if this has already happened. That’s because the brilliant burst of starlight produced by the event won’t reach us for 7,500 years.