to understand and study What are lenticular galaxies?, it is necessary to know exactly what a galaxy is. Galaxies are a set of stars, cosmic material, clouds, dust, gas, dark matter and space bodies that are enchanted to a nucleus by the action of the gravitational force that exists and that can comprise a diameter of millions of light years, and at their time, holding even billions of astral bodies in its orbit. 
What are lenticular galaxies
In this sense, a lenticular galaxy is a type of intermediate galaxy, that is, it is found between a galaxy elliptical and a spiral galaxy that according to the Hubble Sequence is classified as S0. If you want to delve deeper into the classification of the different types of galaxies, this article may be very helpful.
Likewise, lenticular galaxies are with a disk representation, (like spiral galaxies) that have exhausted or lost much or all of their spatial matter (like elliptical galaxies), and therefore lack spiral arms, however Sometimes there is a certain sum of celestial matter, above all dust. They form only 3% of the galaxies in the universe.
Classification of lenticular galaxies
In order to know a little more we can say that the galaxies lenticular are classified as follows:
SO
The S0 class was first specified by Edwin Powell Hubble in 1936 as an intermediate form between elliptical and spiral galaxies; Gerard de Vaucouleurs subsequently purified this series and they are filed in it as: S0 (no central bar), SAB0 (central bar rudiment), and SB0 (with central bar). At the same time, there is also talk of: E/S0 (elliptical galaxies that commemorate a lenticular).
SW-
Regarding the above, S0- (lenticular galaxies very similar to an elliptical), S00 (lenticular galaxies with a certain internal distribution), and S0+ (dust present and in some cases linking with galaxies) are also evident. spirals -mixed symbolization S0/a-); the two classifications - as presence or absence of a central bar and according to whether or not they are visible - agree with each other, as do those that show whether or not there are rings in them. There is more information about the galaxy classification which may be of interest.
A fairly new astronomical categorization system, perfected by astronomers John Kormendy and Ralf Bender, closely parallels the spiral galaxy bulge size classification; thus, there are galaxies S0a-S0b-S0c (with intervening sequences S0ab and S0bc), similar to the Sa, Sab, Sb, Sbc, and Sc classifications for spiral galaxies, which link to dwarf spheroidal galaxies; this system also differentiates between barred and barless lenticular galaxies.
Now that we know what lenticular galaxies are, we now come to know where they come from. This is why we have that these types of galaxies tend to be in excess in rich galaxy clusters, in extortion of the spiral galaxies, and apparently they were once spiral galaxies that shed their gas by erosion with the burning intergalactic gas that fills the intergalactic area and/or by gravitational interactions with other nebulae; two intermediate representations (possibly the same object) between one and the other are languid spiral galaxies, with less space matter and star formation than a similar spiral galaxy, and patient spiral galaxies, with spiral organization but little or no star alignment .
Another proposition that has been made in the same way, on the basis of mathematical pretense, is that lenticular galaxies are the result of the merger between two galaxies propellers of unequal masses and rich in steam. On the other hand, lenticular galaxies may have transformed into that kind of galaxy by consuming their interstellar matter.
However, according to various studies that have been taking place for many years until now, it was possible to know the galaxies lenticular While current galaxies may have arisen from spiral galaxies, the origin of these objects, especially the most massive ones, remains an open question. If you'd like to learn more about how galaxies form, you can visit this article: how galaxies are formed.
In fact, for example, it has also been hinted that most lenticular galaxies may have been as they are today from their inception, noting from time to time stellar alignment buds, rather than spiral galaxies that have degenerated their environment. heavenly.
Characteristics of lenticular galaxies
As mentioned above, we already know what lenticular galaxies are, however we must now know very well how they are represented, that is, what they are like.
Core
The lenticular galaxies have an intensely thick and large nucleus, with a completely flat disc around it, which lacks spirals, this is due to the fact that the procedure spilled a very large amount of gas and dust so there is no great elaboration of stars.
Stars
The stars that are found in this class of galaxies transcend being insufficient in metals, that is, essences much more charged to Helium, for which they are reflected Population II stars, according to the categorization of Walter Blaade. Lenticular galaxies do not have a large number of satellite galaxies or clusters in their interior, however there are still enormous amounts of dust and clouds Space. To learn more about the characteristics of galaxies in general, we recommend this link: characteristics of galaxies.
Location
These kinds of galaxies are usually found mainly in galactic heaps rich in these congregations, in clouds and astral bodies, however, in the same way they can be located in isolated and lonely areas, surrounded by a void of dark body.
Lenticular galaxies in the Universe
Likewise, although lenticular galaxies do not embody a large sum within the Universe, if some exclusive ones with truly extraordinary typologies have been found, then I am talking about Centaurus A and NGC 2787. If you want to read more about the Centaurus A galaxy, you can consult this article.
Centaur A
It is a lenticular galaxy that is passing the Centaurus area, with a view from the planet Earth, in it you can find huge reddish stars, which shows that they are developed and that they have lived millions of years, it is located on the north side of the Milky Way and is only perceptible from the southern hemisphere of our world and is located about 14 million years of him.
This galaxy has a unique appearance, as it is believed that the fact that it is this way and that it has such a dusty disk is due to the fact that it merged with another galaxy in the first 10 million years. Another interesting reason is that, apart from being the fifth brightest galaxy in the sky, is a lenticular galaxy that still displays transformed bursts of stellar alignment, due to the supernovae that have recently occurred. For a more detailed study of this phenomenon, visit how does a supernova occur.
NGC 2787
This galaxy is located 24 million light years from our solar system, and is specialized for being a lenticular galaxy besieged with areas of dark vapor in its disk, near the axis, thanks to the insufficient sum of stars what's wrong with it.
Finally, we have that they are the lenticular galaxies, but in the same way we must consider that in the case of the NGC 2787, which spins more quickly, so it is believed to consist of a supermassive black hole within its axis, however it has not been possible to ratify it.
