NGC 4550 is a
barred lenticular
Lenticular is an adjective often relating to lenses. It may refer to:
* A term used with two meanings in botany: see
* Lenticular cloud, a lens-shaped cloud
* Lenticular galaxy, a lens-shaped galaxy
* Lenticular (geology), adjective describing a ...
galaxy
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...
located 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 ...
of
Virgo that can be seen with
amateur
An amateur () is generally considered a person who pursues an avocation independent from their source of income. Amateurs and their pursuits are also described as popular, informal, autodidacticism, self-taught, user-generated, do it yourself, DI ...
telescopes. It lies at a distance of 50 million
light-years (15.5
mega
Mega or MEGA may refer to:
Science
* mega-, a metric prefix denoting 106
* Mega (number), a certain very large integer in Steinhaus–Moser notation
* "mega-" a prefix meaning "large" that is used in taxonomy
* Gravity assist, for ''Moon-Earth ...
parsecs) from the
Milky Way and is a member of the
Virgo Cluster.
Physical characteristics
While NGC 4550 is not one of the brightest galaxies of the Virgo Cluster, it is notable as it is one of the few galaxies where a large fraction of its stars rotate around the galaxy's center in opposite direction to the others.
[* ]
About her research article on this galaxy,
Vera Rubin wrote: "I discovered from observations of NGC 4550 that in the single disk of this galaxy, half the stars orbit clockwise, and half the stars orbit counterclockwise, both systems intermingled. This observation required that many astronomers modify the manner in which they measured velocities, for computer programs were not then equipped to handle such complexity." She mentions and takes pleasure in the fact that the discovery was made at age 63.
Another, brighter, example is the
spiral galaxy
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''[NGC 7217
NGC 7217 is an unbarred spiral galaxy in the constellation Pegasus.
Features
NGC 7217 is a gas-poor system
whose main features are the presence of several rings of stars concentric to its nucleus: three main ones –the outermost one being of ...]
. The stars of this galaxy are concentrated in two disks of similar size and
surface brightness, one nested within the other
and it has been suggested it is the product of 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 ...
between two previous
disk galaxies
A disc galaxy (or disk galaxy) is a galaxy characterized by a galactic disc, a flattened circular volume of stars. These galaxies may or may not include a central non-disc-like region (a galactic bulge).
Disc galaxy types include:
* Spiral gala ...
, each one counter-rotating with respect to the other.
NGC 4550's center also shows a small amount of
molecular hydrogen and
interstellar dust,
the latter concentrated in a disk surrounding its core
where
is taking place albeit at a very modest level.
References
External links
*
{{DEFAULTSORT:NGC 4550
Lenticular galaxies
Barred lenticular galaxies
Virgo Cluster
Virgo (constellation)
4550
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