One of the most beautiful endings in all of Universe is the death of a huge star.
They release huge amounts of material into the surrounding space, which is carved out by stellar winds and explosion shockwaves, illuminated with the star's light. This is what happens with AG Carinae (15,000 light-years distant), as shown in new Hubble images.
AG Carinae's final moments are more wild than others. It is what we call a luminous blue variable, which are some the most massive, brightest stars in the galaxy.
These rare stars are hot and bright (blue) and have a shorter lifespan than others with a mere few million years.
AG Carinae is about 5 to 7 times as large as the Sun's mass and is only a few millions years old. The star's brightness fluctuates quite a bit due to two warring forces: radiation pressure pushing outward and gravity trying to push the star inward.
(ESA/Hubble, NASA, A. Nota and C. Britt).
Radiation pressure begins to drop at the end of a star’s life. This happens when it runs out of fuel to fuse to hydrogen. The star contracts as the star gets closer to its stellar core. This causes material to heat up.
The star then erupts due to the heating, which ejects material outward. AG Carinae's shell, which looks like an iris around an eye, is the result of a similar eruption. It occurred around 10,000 years ago and contained approximately 15 solar masses of material.
The colors in the Hubble images represent different types of material. The star's ionized gas, mainly hydrogen and nitrogen, is represented by the red color. The star's light illuminates the blue color as dust around it.
The star's strong wind blows at speeds of up to one million kilometers an hour (670,000 miles an hour) and creates the shapes and cavities in the dust.
(ESA/Hubble, NASA, A. Nota and C. Britt).
The wind blows faster than the gas nebula expands, at 250,000 km/h. When it catches up, the wind hits the gas, pushing it forward and creating a cavity around star. The stellar wind also cuts out the filaments and bubbles in the dust.
AG Carinae remains unstable and will eventually run out of hydrogen from repeated outbursts. This process is already underway. AG Carinae's main sequence days will end in a supernova when this evolutionary stage is complete.
Astronomers predict that the core of the black hole will burst, leaving behind one the most mysterious objects in the Universe.
Download wallpaper-sized versions the composite image from the ESA Hubble site.
