Credit: ESA/Hubble & NASA
This entrancing image shows a few of the tenuous
threads that comprise Sh2-308, a faint and wispy shell of gas located
5200 light-years away in the constellation of Canis Major (The Great Dog).
Sh2-308 is a large bubble-like structure wrapped around an extremely large, bright type of star known as a Wolf-Rayet Star
— this particular star is called EZ Canis Majoris. These type of stars
are among the brightest and most massive stars in the Universe, tens of
times more massive than our own Sun, and they represent the extremes of
stellar evolution. Thick
winds continually poured off the progenitors of such stars, flooding
their surroundings and draining the outer layers of the Wolf-Rayet
stars. The fast wind of a Wolf-Rayet star therefore sweeps up the
surrounding material to form bubbles of gas.
EZ Canis Majoris is responsible for creating the bubble of Sh2-308 — the
star threw off its outer layers to create the strands visible here. The
intense and ongoing radiation from the star pushes the bubble out
further and further, blowing it bigger and bigger. Currently the edges
of Sh2-308 are some 60 light-years apart!
Beautiful as
these cosmic bubbles are, they are fleeting. The same stars that form
them will also cause their death, eclipsing and subsuming them in
violent supernova explosions.
Source: ESA/Hubble/Potw
