Credit: ESA/Hubble & NASA and S. Smartt (Queen's University Belfast)
Acknowledgement: Robert Gendler
This new image of the spiral galaxy NGC 3521
from the NASA/ESA Hubble Space Telescope is not out of focus. Instead,
the galaxy itself has a soft, woolly appearance as it a member of a
class of galaxies known as flocculent spirals.
Like
other flocculent galaxies, NGC 3521 lacks the clearly defined, arcing
structure to its spiral arms that shows up in galaxies such as Messier 101, which are called grand design spirals.
In flocculent spirals, fluffy patches of stars and dust show up here
and there throughout their discs. Sometimes the tufts of stars are
arranged in a generally spiralling form, as with NGC 3521, but
illuminated star-filled regions can also appear as short or
discontinuous spiral arms.
About 30 percent of galaxies share NGC
3521's patchiness, while approximately 10 percent have their
star-forming regions wound into grand design spirals.
NGC 3521 is located almost 40 million light-years away in the constellation of Leo (The Lion). The British astronomer William Herschel discovered the object in 1784. Through backyard telescopes, NGC 3521 can have a glowing, rounded appearance, giving rise to its nickname, the Bubble Galaxy.
Source: ESA/Hubble - Space Telescope
