© NASA, ESA, STScI
Spectacular image of the luminous blue variable star AG Carinae released by Hubble for it’s 31st launch anniversary.
Astrophotography is one of the most gratifying parts of space exploration, and there's nothing better at it than
Hubble. Recently, it celebrated the 31st anniversary of its launch by taking a spectacular image of one of the most impressive stars in the sky -
AG Carinae.
In the not too distant future, Hubble, or a successor, might be able to capture an even more spectacular display from the star when it goes supernova.
AG Carinae, located appropriately in the constellation
Carina, is one of the most luminous stars in the sky, though its apparent brightness on Earth is somewhat diminished give its 20,000 light year distance from Earth. The star is famous for a number of reasons, including that it is one of only 50 known
luminous blue variable stars.
Luminous blue variables are extremely short lived and violent, barely balancing between exploding into a supernova and collapsing under its own weight into a black hole. As part of their life cycle, they occasionally emit a spectacular outburst that creates a kind of glowing shell around them, as can be seen in the Hubble image of AG Carinae.
Outbursts like the one in the picture only happen once or twice in a luminous blue variable's lifetime. They occur when radiation pressure from the interior of the star expands it out to such an immense size that it pushes material out of itself, then collapses back into a more stable state for potentially millions of years.
Comment: We've barely begun to understand what underpins the health of our soil, which, in turn, is what sustains our health: