spiral galaxy
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''magnitude about 11.5, located about 81 million
light year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s away in the
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
Virgo III Groups
The Virgo III Groups, or Virgo III Cloud, are a series of at least 75 galactic clusters and individual galaxies stretching approximately off the eastern edge of the Virgo Supercluster. Parts of it are in the constellations Virgo, Libra, and Serp ...
strung out to the east of the Virgo Supercluster of galaxies.
As seen from the Earth, it is inclined by an angle of 18° to the line of sight along a position angle of 145°. The morphological classification in the De Vaucouleurs system is SA(s)d, indicating a pure spiral structure with loosely wound arms. However, optical images of the galaxy indicate the presence of a weak bar structure spanning an angle of 12″ across the nucleus. There is a dwarf galaxy located around to the southeast of NGC 5668, and the two may be gravitationally interacting.
Three
supernova
A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...
e have been observed in this galaxy: SN 1952G, SN 1954B, and SN 2004G. The last, a type II supernova, was initially imaged on January 19, 2004, at 43" to the west and 12".5 south of the galaxy core. High velocity clouds of
neutral hydrogen
The hydrogen line, 21 centimeter line, or H I line is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation has a precise frequency of , w ...
have been observed in NGC 5668, which may have their origin in supernova explosions and strong
stellar wind
A stellar wind is a flow of gas ejected from the 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 spherically symmetric.
D ...