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 four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The R ...
located in the constellation
Aries
Aries may refer to:
*Aries (astrology), an astrological sign
*Aries (constellation), a constellation of stars in the zodiac
Arts, entertainment and media
* ''Aries'' (album), by Luis Miguel, 1993
* ''Aries'' (EP), by Alice Chater, 2020
* "Aries" ...
. It is located at a distance of circa 120 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 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 (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline H ...
tidal force
The tidal force is a gravitational effect that stretches a body along the line towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for diverse phenomen ...
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 the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
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 companies, other business organizations, or their operating units are transferred to or consolidated with another company or business organization. As an aspect ...
of two galaxies, maybe two gas rich galaxies, maybe
spiral
In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point.
Helices
Two major definitions of "spiral" in the American Heritage Dictionary are: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
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed syst ...
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 conven ...
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 galaxies ...
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 commonly refers to:
* New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy
NGC may also refer to:
Companies
* NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998
* Nati ...
. 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.