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I love imaging galaxies, especially the galactic ones like spirals and quasars. Last year, when I started astrophotography, I discovered that it was possible to photograph galaxies that were millions of light-years away! On this page, though, I want to focus on one kind of galaxy, the lenticular type of galaxy from the Hubble sequence, and help you understand why it is so important to astronomers.
A lenticular galaxy, also known as a galactic bulge, is a type of galaxy found in the Milky Way. It has a bulge in its centre and a flat disc surrounding it, lacking the spiral arms typically seen in other galaxies, such as spirals. The formation of lenticular galaxies is believed to occur when two spiral galaxies collide, according to astronomers.
As we shall see, lenticular galaxies are important to our understanding of the universe, and personally, I have always found them to be quite appealing deep-sky astrophotography targets. I have managed to image a few of these, and one example I have photographed is the Needle Galaxy.
Before we go further, in case you’re wondering, check out my guide on how you can get into astrophotography cheaply.
Let’s now look more closely at the form and importance of irregular galaxies, galactic galaxies, elliptical galaxies, and spiral galaxies.
Why are lenticular galaxies important?
Astronomers study galaxies in general to better understand the organisation and formation of matter in the universe. Galaxies represent physics working on a huge scale, whereas quantum physics is the exact opposite. If we understand how galaxies formed and organised themselves into what we see today, together with what we learn about subatomic-level physics, we can better understand how the universe works. See this article, published by Nasa, for more information about how the James Webb Telescope will try to help us understand the nature and formation of galaxies better and solve other related questions we have about the universe.
Now let’s consider lenticular galaxies specifically, which are a type of galactic structure, and what scientists can learn from them. Lenticular galaxies have a unique spiral shape and emit a distinct light that can provide valuable insights.
Lenticular galaxies are important for several reasons:
- They are the first quasi-stellar objects (QSOs) that Edwin Hubble discovered and observed in 1923. This discovery helped Hubble make the statement that we live in an expanding universe.
- Lenticular galaxies provide a unique observational perspective on how dark matter is distributed in space. There appears to be dark matter in the outer area of this type of galaxy in the form of a halo.
- The study of lenticular galaxies can help astronomers understand the process of star formation (see this article published by Phys.org for more about this).
What is a Lenticular Galaxy Made of?
Lenticular galaxies are composed of older stars because the theory is that they are the result of a collision between two spiral galaxies. This means that the galaxy must at least be as old as the oldest of the pair of original galaxies. In fact, more than that, because we also need to add the time that was needed for the final galaxy to form after the collision. Check out my images of Markarian’s Chain where you can see a few lenticular galaxies.
Despite the above theory of how these types of galaxies are formed, there is much doubt and confusion about this question. Some of these points are raised in this article by Sidney Van Den Bergh (1999).
When we observe these kinds of galaxies, we are looking at a long period of the history of star and galaxy formation. This is what makes them so important to astronomers studying them.
These lenticular galaxies, which have a spiral bulge and disc, are not very common, but they are more frequently found in clusters, especially in the Virgo Cluster.
If you are interested in improving your astrophotography, then go look at my 5 tips to take better astrophotos now.
And here is another page I’ve written for you if you want to know what’s so great about astrophotography.
Lenticular galaxies are also known as lens-shaped galaxies
Lenticular galaxies, also known as lens-shaped galaxies, are oval or elliptical in shape, resembling a lentil. They are classified as elliptical galaxies due to their bulge and disc structure. These galaxies are formed when two colliding spiral galaxies merge, creating a new galaxy. Additionally, other galaxy collisions can also result in the formation of lenticular galaxies.
The lens-shaped galaxy has an outer disc that surrounds the nucleus and an inner disc that contains young stars, dust, and a bulge. Since they are the result of two spiral galaxies colliding, lenticular galaxies have more gas, dust, and a bulge than other types.
Examples of Lenticular Galaxies
Lenticular galaxies, also known as spiral galaxies, are galaxies that have a disc, a bulge, and an extended halo.
Lenticular galaxies, also known as disc galaxies, may resemble elliptical galaxies at first glance. However, they possess a spiral-like bulge and disc structure, containing more stars and dust than their elliptical counterparts. While lenticular galaxies typically lack active star formation, those in close proximity to the Milky Way may exhibit star-forming activity.
The Spindle Galaxy
The Spindle Galaxy, located within the constellation of Coma Berenices, is a small bulge of stars near its centre. Discovered in 1845 by James Dunlop, this galaxy is an example of a spiral galaxy.
The Spindle Galaxy, with its disc, has been classified as a lenticular galaxy, but some astronomers argue it is actually a dwarf spiral galaxy with a bulge.
There are two main arguments for why the Spindle Galaxy may not be a lenticular galaxy: first, the disc of the galaxy lacks enough gas to form new stars, and second, it lacks an outer ring of old red stars typically found in elliptical galaxies. These factors suggest that the Spindle Galaxy does not exhibit a spiral or bulge structure.
The Sombrero Galaxy
The Sombrero Galaxy (see my photo of the bulge at the beginning of this article) is classified as an elliptical galaxy, although some prefer to classify it as a spiral disc.
Lenticular Galaxies and How They Are Shaping the Future of the Universe
Lenticular galaxies are unique for their disk-like shape, distinct from spiral or elliptical shapes. They host two supermassive black holes, which, as they orbit each other, can cause gravitational waves and produce bright bursts of light. These galaxies have a bulge.
Lenticular galaxies, with their spiral and disc shapes, are shaping the future of the universe as we know it.
How Did Lenticular Galaxies Come to Be?
Lenticular galaxies, with their striking spiral or disc shapes, are a rare celestial spectacle in the universe. So how did these galaxies come about?
The prevalent theory is that collisions between two or more galaxies are what create lenticular galaxies. The collision causes the gas and stars to accumulate in one area, producing a disc shape. These discs are usually seen when looking at them from one side, but if you view them from the other side, it looks like a spiral galaxy.
Lenticular galaxies, including spiral ones, are crucial for comprehending the universe as they provide insights into its history.
Firstly, they appear to be relatively rare; there are only about 25 known lenticular galaxies in the entire universe. Secondly, these galaxies contain some of the oldest stars in the universe. Thirdly, they can provide insight into how gas is distributed in the galaxy. Personally, one of the favourites that I’ve been able to photograph is the Sombrero Galaxy, which looks like a giant UFO! If you want to photograph galaxies you will need to buy a good quality telescope, but how much should you pay? Find out how much different telescopes cost here.