UGC 8320
Encyclopedia
UGC 8320 is a dwarf
irregular galaxy
located in the constellation Canes Venatici
. The galaxy measures approximately 4 × 1.5 kiloparsecs (13,000 × 4,900 lightyears) and has a large number of H II region
s scattered across most of the observable face. Nearly all of the resolvable stars above magnitude
19.5 are blue giant
s of class O or B and the entire galaxy has a distinct blue appearance when viewed in visible light
, suggesting that it is in a state of vigorous star formation
. A majority of the H II regions and associated blue giants are concentrated in a band extending from the center of the galaxy to the upper-right end of the disc when viewed from our vantage point on Earth
. Another large cluster of stars is located at the lower-left end of the galaxy and a third is located directly below the center though the latter does not appear to be associated with any H II regions.
Although a number of lists of basic information about galaxies (such as the NASA/IPAC Extragalactic Database
) give distances of around 5.2 megaparsecs (17 million lightyears) for UGC 8320, more recent studies indicate a distance of closer to 4 Mpc (13 million ly). Based on the revised distance estimates, the galaxy is probably a companion of UGC 8308 and is located near UGC 8331
and UGC 8215. UGC 8320 is sometimes included in the M51 Group
of galaxies although there is not a general consensus on whether it is a member or not.
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...
located in the constellation Canes Venatici
Canes Venatici
Canes Venatici is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for "hunting dogs", and the constellation is often depicted in illustrations as representing the dogs of Boötes the...
. The galaxy measures approximately 4 × 1.5 kiloparsecs (13,000 × 4,900 lightyears) and has a large number of H II region
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived, blue stars forged in these regions emit copious amounts of ultraviolet light, ionizing the surrounding gas...
s scattered across most of the observable face. Nearly all of the resolvable stars above magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
19.5 are blue giant
Blue giant
In astronomy, a blue giant is a star with a spectral type of O or B and a luminosity class of III...
s of class O or B and the entire galaxy has a distinct blue appearance when viewed in visible light
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...
, suggesting that it is in a state of vigorous 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...
. A majority of the H II regions and associated blue giants are concentrated in a band extending from the center of the galaxy to the upper-right end of the disc when viewed from our vantage point on 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...
. Another large cluster of stars is located at the lower-left end of the galaxy and a third is located directly below the center though the latter does not appear to be associated with any H II regions.
Although a number of lists of basic information about galaxies (such as the NASA/IPAC Extragalactic Database
NASA/IPAC Extragalactic Database
The NASA/IPAC Extragalactic Database is an on-line astronomical database for astronomers that collates and cross-correlates astronomical information on extragalactic objects...
) give distances of around 5.2 megaparsecs (17 million lightyears) for UGC 8320, more recent studies indicate a distance of closer to 4 Mpc (13 million ly). Based on the revised distance estimates, the galaxy is probably a companion of UGC 8308 and is located near UGC 8331
UGC 8331
UGC 8331 is an irregular galaxy located in the constellation Canes Venatici. It is a member of the M51 Group of galaxies and measures approximately 5 x 1.5 kiloparsecs . The galaxy's large-scale structure is very unorganized and it has two clusters of stars in its outer portions in addition to the...
and UGC 8215. UGC 8320 is sometimes included in the M51 Group
M51 Group
The M51 Group is a group of galaxies located in Canes Venatici. The group is named after the brightest galaxy in the group, the Whirlpool Galaxy...
of galaxies although there is not a general consensus on whether it is a member or not.