M33: Triangulum Galaxy
From NASA’s Astronomy Picture of the
Day
The small, northern
constellation Triangulum harbors
this magnificent face-on spiral galaxy, M33. Its popular names include the
Pinwheel Galaxy or just the Triangulum Galaxy.
M33 is over 50,000
light-years in diameter, third largest in the Local Group of
galaxies after the Andromeda Galaxy (M31), and our own Milky Way.
About 3 million
light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in
these two galaxies would likely have spectacular views of each other's grand
spiral star systems.
As for the view from
planet Earth, this sharp
composite image, a 25 panel mosaic, nicely shows off M33's blue star
clusters and pinkish star
forming regions that trace the galaxy's loosely wound spiral arms.
In fact, the cavernous NGC 604 is
the brightest star forming region, seen here at about the 1 o'clock position
from the galaxy center. Like M31, M33's population of well-measured variable
stars have helped make this nearby spiral a cosmic yardstick for establishing the
distance scale of
the Universe.
Image Credit & Copyright: Robert
Gendler, Subaru Telescope (NAOJ)
Image data: Subaru Telescope, Robert Gendler, Brigham Young University Obs., Johannes Schedler
Image data: Subaru Telescope, Robert Gendler, Brigham Young University Obs., Johannes Schedler