NGC 1569 is a

dwarf Dwarf, dwarfs or dwarves may refer to: Common uses *Dwarf (folklore), a supernatural being from Germanic folklore * Dwarf, a human or animal with dwarfism Arts, entertainment, and media Fictional entities * Dwarf (''Dungeons & Dragons''), a sh ...

irregular galaxy An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearan ...

Camelopardalis Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative form ...

. The galaxy is relatively nearby and consequently, the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

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 previously thought, meaning it is a member of the IC 342 group of galaxies.

Physical characteristics

NGC 1569 is smaller than the

Small Magellanic Cloud The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of approximately 7 bill ...

, but brighter than the

Large Magellanic Cloud The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way. At a distance of around , the LMC is the second- or third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal Galaxy, Sagittarius Dwarf ...

Starburst

NGC 1569 is characterized by a large starburst. It has formed stars at a rate 100 times greater than that of the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

during the last 100 million years.Hubble Resolves Puzzle about Loner Starburst Galaxy
Newswise, Retrieved on November 17, 2008. It contains two prominent super star clusters with different histories. Both clusters have experienced episodic

star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

. 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), 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). Super star cluster B, located near the center of the galaxy, contains an older stellar population of red giants and

red supergiants Red supergiants (RSGs) are stars with a supergiant luminosity class (Stellar classification#Yerkes spectral classification, Yerkes class I) and a stellar classification K or M. They are the List of largest stars, largest stars in the universe in t ...

. Both of these star clusters are thought to have masses equivalent to the masses of the

globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...

s in the

(approximately (6-7) × 10⁵

solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es). Numerous smaller star clusters, some of them having masses similar to those of small globular clusters or

R136 R136 (formerly known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud. W ...

in the Large Magellanic Cloud, with relatively young ages (between 2 million years and 1 billion years) have also been identified. These results, along with the results from other dwarf galaxies such as the

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. NGC 1569

The numerous

supernovae A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original ob ...

produced in the galaxy as well as the strong

stellar wind A stellar wind is a flow of gas ejected from the stellar atmosphere, upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spheri ...

s of its stars have produced filaments and bubbles of ionized hydrogen with respective sizes of up to 3,700 and 380

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s that shine excited by the light of the young stars contained within them and that are conspicuous on images taken with large telescopes. 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. 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.

Blueshift

The

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

of NGC 1569 is

blueshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

ed. This means that the galaxy is moving towards the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. In contrast, the spectra of most other galaxies are

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

ed because of the expansion of the universe.

Environment

The dwarf irregular galaxy UGCA 92 is often assumed to be a companion of NGC 1569; however, its relationship to the starburst the latter is experiencing is unclear, with some authors suggesting UGCA 92 has not started it and others suggesting it has interacted with NGC 1569, being connected with it by a tidal tail and several filaments of neutral hydrogen; however, it is still unclear if those structures are associated with them or actually within the Milky Way, being unrelated with those two galaxies.

References

External links

NGC 1569 at ESA/Hubble
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NGC 1569 at Constellation Guide
{{DEFAULTSORT:Ngc 1569 Dwarf irregular galaxies Camelopardalis 1569 03056 15345 210 IC 342/Maffei Group