NGC 680 is an

elliptical galaxy An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the three main galaxy morphological classification, classes of galaxy described by Edwin Hubble in his Hub ...

located in the constellation

Aries Aries may refer to: *Aries (astrology), an astrological sign *Aries (constellation), a constellation in the zodiac Arts, entertainment and media * ''Aries'' (album), by Luis Miguel, 1993 * ''Aries'' (EP), by Alice Chater, 2020 * "Aries" (song), ...

. It is located at a distance of circa 120 million

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 from Earth, which, given its apparent dimensions, means that NGC 680 is about 100,000 light years across. It was discovered by

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

on September 15, 1784.

Characteristics

NGC 680 appears asymmetrical, probably due to interactions with other galaxies. The

tidal force The tidal force or tide-generating force is the difference in gravitational attraction between different points in a gravitational field, causing bodies to be pulled unevenly and as a result are being stretched towards the attraction. It is the ...

s have disturbed the shape of the galaxy and have created arcs, shells and an asymmetric envelope. It also features a patchy dusty feature. The

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

gas of the galaxy forms two large diffuse stellar plumes that may be associated with tidal tails. One plume extends to the south-east and the other to the north-west and have projected lengths of 75 and 60 kpc accordingly. However, the galaxy does not have a kinematically decoupled nucleus. All these characteristics indicate that the current galaxy was created by the

merger Mergers and acquisitions (M&A) are business transactions in which the ownership of a company, business organization, or one of their operating units is transferred to or consolidated with another entity. They may happen through direct absorpt ...

of two galaxies, maybe two gas rich galaxies, maybe

spiral In mathematics, a spiral is a curve which emanates from a point, moving further away as it revolves around the point. It is a subtype of whorled patterns, a broad group that also includes concentric objects. Two-dimensional A two-dimension ...

s, based on the amount of gas located around the galaxy. The lack of detection of molecular gas indicated that the merger took place 1-2 billion years ago. The merger remnant is characterised as a "fast rotator" that indicates either that the galaxy retained the

angular momentum Angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of Momentum, linear momentum. It is an important physical quantity because it is a Conservation law, conserved quantity – the total ang ...

of the original galaxy or that the two galaxies merged in a way that they attained angular momentum. The mean age of the stellar population of the central 0.3 kpc of NGC 680 is 7.8 billion years, while for the central 2.6 kpc the mean age is 6.5 billion years.

Ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

ised gas has been detected in the nucleus of the galaxy, it is probably created by the gas emitted by stars at the end of their life. An arc of bluer and younger stars has been detected east of the galaxy.

Nearby galaxies

NGC 680 is a member of a

galaxy group A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxi ...

known as the NGC 691 group. Other members of the group include IC 163, NGC 678,

NGC 691 NGC 691 is an unbarred spiral galaxy located in the constellation Aries. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 691 is about 130,000 light years across. It was ...

NGC 694 NGC 694 is a spiral galaxy approximately 136 million light-years away from Earth in the constellation of Aries. It was discovered by German astronomer Heinrich Louis d'Arrest on December 2, 1861 with the 11-inch refractor at Copenhagen. Nearby ...

IC 167 IC 167 is a barred spiral galaxy in the constellation of Aries. It was first reported by Bigourdan in 1891 and included in Dreyer's first ''Index Catalogue''. Galaxy group information IC 167 is a member of the NGC 697 group. There is some evid ...

, and

NGC 697 NGC may refer to: Companies * NGC Corporation, the name of US electric company Dynegy, Inc. from 1995 to 1998 * National Gas Company of Trinidad and Tobago, a state-owned natural gas company in Trinidad and Tobago * National Grid plc, a former nam ...

. NGC 680 forms a pair with NGC 678, located 5.5 arcminutes to the northwest, and IC 1730 lies 3.7 arcminutes northwards. Hydrogen emission surrounds both NGC 680 and the nearby NGC 678 and an HI tail has been found to extend towards NGC 691, with the total of this cloud HI mass estimated to by about . This gas was probably stripped by NGC 678 after a close encounter with NGC 680. However, with the use of deep photography, a stellar bridge between the two galaxies has not been detected, nor between NGC 680 and IC 1730.

References

External links

NGC 680 on SIMBAD
{{DEFAULTSORT:NGC 680 Elliptical galaxies Peculiar galaxies Aries (constellation) 0680 01286 06719 Astronomical objects discovered in 1784 Discoveries by William Herschel