NGC 1569 is a
dwarfirregular galaxy in
Camelopardalis. The galaxy is relatively nearby and consequently, the
Hubble Space Telescope can easily resolve the stars within the galaxy.
[3] The distance to the galaxy was previously believed to be only 2.4
Mpc (7.8
Mly).
[4] However, in 2008 scientists studying images from Hubble calculated the galaxy's distance at nearly 11 million light-years away, about 4 million light-years farther than previous thought, meaning it is a member of the
IC 342 group of galaxies.
[2][5]Contents
Physical characteristicsNGC 1569 is smaller than the
Small Magellanic Cloud, but brighter than the latter or the
Large Magellanic Cloud[6]StarburstNGC 1569 is characterized by a large
starburst. It has formed stars at a rate 100 times greater than that of the
Milky Way during the last 100 million years.
[5] It contains two prominent
super star clusters with different histories.
[3][7] Both clusters have experienced episodic
star formation. Super star cluster A, located in the northwest of the galaxy and actually formed of two close clusters (NGC 1569 A1 and NGC 1569 A2),
[8] contains young stars (including
Wolf-Rayet stars) that formed less than 5 million years ago (in NGC 1569 A1) as well as older red stars (in NGC 1569 A2).
[7][9] Super star cluster B, located near the center of the galaxy, contains an older stellar population of
red giants and
red supergiants.
[3][7][9] Both of these star clusters are thought to have masses equivalent to the masses of the
globular clusters in the
Milky Way (approximately (6-7) × 105
solar masses[2]). Numerous smaller star clusters, some of them having masses similar to those of small globular clusters or
R136 in the Large Magellanic Cloud, with relatively young ages (between 2 million years and 1 billion years) have also been identified.
[3] These results, along with the results from other dwarf galaxies such as the
Large Magellanic Cloud and
NGC 1705, demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.
Center of NGC 1569 as imaged by the
Hubble Space Telescope. At center left the two super star clusters NGC 1569 A1 and NGC 1569 A2 are visible.The numerous
supernovae produced in the galaxy as well as the strong
stellar winds of its stars have produced filaments and bubbles of
ionized hydrogen with respective sizes of up to 3,700 and 380
light years that shine excited by the light of the young stars contained within them and that are conspicuous on images taken with large telescopes.
[5]The NGC 1569 starburst is believed to have been triggered by interactions with other galaxies of the IC 342 group, in particular a nearby cloud of
neutral hydrogen.
[5][10] A 2013 study suggested the presence of tidal tails linking this galaxy with
IC 342 and the dwarf galaxy
UGCA 92 (see below) whose nature, however, is unclear and may actually be structures within our galaxy.
[11]BlueshiftThe
spectrum of NGC 1569 is
blueshifted.
[1] This means that the galaxy is moving towards the
Earth. In contrast, the spectra of most other galaxies are
redshifted because of the expansion of the universe
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