NGC 1569
Encyclopedia
NGC
1569 is a dwarf
irregular galaxy
in Camelopardalis
. While this faint galaxy is not a popular amateur astronomy target, it is well studied by professional astronomers, who are interested in the history of star formation
within the galaxy. The galaxy is relatively nearby. Consequently, the Hubble Space Telescope
can easily resolve the stars within the galaxy. The distance to the galaxy was previously believed to be only 2.4 Mpc
(7.8 Mly
). 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.
s with different histories.
Both clusters have experienced episodic star formation
. Super star
cluster A, located in the northwest of the galaxy, contains young stars
(including Wolf-Rayet stars) that formed less than 5 million years ago as
well as older red stars.
Super star cluster B, located near the center of the galaxy, contains an older
stellar population of red giants and red supergiants.
Both of these star clusters are thought to have masses equivalent to the masses of the globular cluster
s in the Milky Way
. Numerous smaller star clusters with relatively young ages have also been identified.
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.
is blueshifted. This means that the galaxy is moving towards the Earth
. In contrast, the spectra of most other galaxies are redshift
ed because of the expansion of the universe.
New General Catalogue
The New General Catalogue of Nebulae and Clusters of Stars is a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects...
1569 is a dwarf
Dwarf galaxy
A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars...
irregular galaxy
Irregular galaxy
An irregular galaxy is a galaxy that does not have a distinct regular shape, like a spiral or an elliptical galaxy. The shape of an irregular galaxy is uncommon – they do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a...
in Camelopardalis
Camelopardalis
Camelopardalis is a large but faint constellation in the northern sky. The constellation was introduced in 1612 by Petrus Plancius. Some older astronomy books give an alternative spelling of the name, Camelopardus.-Etymology:...
. While this faint galaxy is not a popular amateur astronomy target, it is well studied by professional astronomers, who are interested in the history of star formation
Star formation
Star formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
within the galaxy. The galaxy is relatively nearby. Consequently, the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
can easily resolve the stars within the galaxy. The distance to the galaxy was previously believed to be only 2.4 Mpc
Parsec
The parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....
(7.8 Mly
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
). 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.
Star formation
NGC 1569 contains two prominent super star clusterSuper star cluster
A super star cluster is a very large region that is thought to be the precursor of a globular cluster. They typically contain a very large number of young, massive stars that ionize a surrounding H II region, similar to our Milky Way's so-called "Ultra dense H II regions ". An SSC's H II region is...
s with different histories.
Both clusters have experienced episodic star formation
Star formation
Star formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
. Super star
cluster A, located in the northwest of the galaxy, contains young stars
(including Wolf-Rayet stars) that formed less than 5 million years ago as
well as older red stars.
Super star cluster B, located near the center of the galaxy, contains an older
stellar population of red giants and red supergiants.
Both of these star clusters are thought to have masses equivalent to the masses of the globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
s in the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
. Numerous smaller star clusters with relatively young ages have also been identified.
These results, along with the results from other dwarf galaxies such as the Large Magellanic Cloud
Large Magellanic Cloud
The Large Magellanic Cloud is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs , the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal and Canis Major Dwarf Galaxy lying closer to the center...
and NGC 1705
NGC 1705
NGC 1705 is a peculiar lenticular galaxy in the constellation Pictor. It is estimated to be approximately 17 million light-years from the Earth. It is a member of the Dorado Group.-External links:*...
, demonstrate that star formation in dwarf galaxies does not occur continuously but instead occurs in a series of short, nearly instantaneous bursts.
Blueshift
NGC 1569 is exceptional in that its spectrumSpectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
is blueshifted. This means that the galaxy is moving towards the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. In contrast, the spectra of most other galaxies are redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
ed because of the expansion of the universe.