The Great Eruption of Eta Carinae

6a00d8341bf7f753ef01310fc0bdd2970c.jpg Eta-carinae-big Situated just East of the Keyhole Nebula in the Southern Sky, lies the super-luminous eruptive star eta Carinae at a distance of only about 7500 light years from Earth. This strange star is is over one million times brighter than our sun and over one hundred times more massive, making it possibly the most massive star in the Galaxy. In the mid-1800s the star experienced an outburst named the "Great Eruption."  Eta Carinae produced almost as much visible light as a supernova explosion, but it survived.

During this time a large amount (1-2 solar masses) of material was ejected at high velocity. This material cooled and formed the expanding gas and dust cloud we see today. The star is thought to be consuming its nuclear fuel at an incredible rate, while quickly drawing closer to its ultimate explosive demise.

The composite image of the Eta Carinae from NASA's Chandra X-ray Observatory and Hubble Space Telescope shows the remnants of a massive eruption from the star during the 1840s.

When Eta Carinae does explode, it will be a spectacular fireworks display seen from Earth, perhaps rivaling the moon in brilliance. Its fate has been foreshadowed by the recent discovery of SN2006gy, a supernova in a nearby galaxy that was the brightest stellar explosion ever seen. The erratic behavior of the star that later exploded as SN2006gy suggests that Eta Carinae may explode at any time.

Eta Carinae, a star between 100 and 150 more massive than the Sun, is near a point of unstable equilibrium where the star's gravity is almost balanced by the outward pressure of the intense radiation generated in the nuclear furnace. This means that slight perturbations of the star might cause enormous ejections of matter from its surface. In the 1840s, Eta Carinae had a massive eruption by ejecting more than 10 times the mass of the sun, to briefly become the second brightest star in the sky. This explosion would have torn most other stars to pieces but somehow Eta Carinae survived.

The Daily Galaxy via  Chandra X-ray Center/ESO

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