A stunning new image of one of the Milky Way's nearest
galactic neighbors, Barnard's Galaxy, reveals rich star formation and
curiously-shaped nebulas.
At the relatively close distance of about 1.6 million
light-years, Barnard's Galaxy is a member of the Local Group, an archipelago of
galaxies that includes our home, the
Milky Way.
The galaxy, also known as NGC 6822, was discovered by the
American astronomer Edward Emerson Barnard in 1884.
The new image, taken by one of the telescopes at the
European Southern Observatory in La Silla, Chile, shows Barnard's Galaxy beneath
a sea of foreground stars in the direction of the constellation of Sagittarius
(the Archer).
Barnard's Galaxy is a dwarf galaxy that lacks the spiral
arms of its neighbors, the Milky Way, Andromeda and the Triangulum
galaxies. Barnard's Galaxy is also much smaller than some of its Local Group neighbors, with about 10
million stars — a far cry from the Milky Way's estimated 400 billion.
Reddish nebulas in the new image reveal regions of active
star formation, where young, hot stars heat up nearby gas clouds.
Prominent in the upper left of the image is a striking
bubble-shaped nebula. At the nebula's center, a clutch of massive, scorching
stars send waves of matter smashing into the surrounding interstellar material,
generating a glowing structure that appears ring-like from our perspective.
Other similar ripples of heated matter thrown out by feisty young stars are
dotted across Barnard's Galaxy.
Irregular dwarf galaxies like Barnard's Galaxy get their
random, blob-like forms from close encounters with or "digestion" by
other galaxies. When two
galaxies collide, their gravitational interaction can warp the shapes of
the galaxies.
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