Located in the shape of a triangle, Triangulum is the third-largest galaxy among our Local Group. The Milky Way, Andromeda Galaxy, and Triangulum are all great spiral galaxies. So much so that when images of the galaxy appear on screens they depict arms loosely wound around a core from which stars dangle like lights on an urn.
Facts About The Triangulum Galaxy
- The Triangulum Galaxy is a spiral galaxy with no central bar and its loosely wound arms emanate from the galactic core.
- Recent studies have shown that the Triangulum Galaxy contains a nebula – or HII region, which is what scientists call gas and dust clouds.
- You might mistake it for the Pinwheel Galaxy, but Messier 101 is actually a different galaxy altogether.
- The Triangulum Galaxy has been interacting with the nearby Andromeda Galaxy for a long time and will continue to do so in the future.
- The Triangulum Galaxy is the most active galaxy in terms of making stars. It can be found scattered throughout its spiral arms and has a higher star birth rate than our very own Andromeda Galaxy.
- Andromeda and the Triangulum Galaxy are linked by streams of hydrogen gas, which have been created from specific stars.
- Astronomers believe that the merging of Andromeda and Milky Way will also affect Triangulum Galaxy. The future merger may tear it apart or make it a part of an elliptical galaxy larger than what is currently there.
- The galaxy was spotted with the naked eye, but it’s much easier to find using binoculars or a telescope.
- The largest stellar-mass black hole ever discovered sits in the center of a galaxy called Triangulum.
- The Triangulum Galaxy has an apparent magnitude of 5.72, which is indicative of how bright the galaxy appears from Earth’s perspective.
Triangulum Galaxy Profile
| Designation: | Messier 33 or NGC 598 |
| Type: | Spiral Galaxy |
| Diameter: | 50,000 light-years |
| Distance from Earth: | < 3,000,000 light-years |
| Mass: | 50,000,000 times the mass of the Sun |
| Location: | Triangulum Constellation |
| Group: | Local Group |
| When it was discovered: | 1764 |
| Estimated Number of Stars: | 40,000,000,000 ( 40 billion ) |
The Triangulum galaxy is under half the size of our own Milky Way and has a spiral structure just like ours, but it’s much smaller in proportion.
The Triangulum Galaxy is officially the second-closest galaxy to our own Milky Way and Andromeda, at about 3 million light-years away. The Local Group of galaxies has around 50 members including ours!
Triangulum Galaxy History
It’s always nice to discover new galaxies, even if you weren’t the first person in history to do so. Giovanni Battista Hodierna was an Italian astronomer that discovered the Triangulum galaxy sometime before 1654.
His landmark publication of “De systemate orbis cometici” held a passing reference that some think could be about the Triangulum Galaxy.
In 1764, Charles Messier cataloged the Triangulum galaxy as M33 in the Messier catalog.
William Herschel, an astronomer who is most well-known for discovering Uranus in the late 1700s made note of a galaxy he observed.
At the time, many of these observations were thought to be “spiral nebulae” and that they made up part of our galaxy.
In the 1920s, Edwin Hubble discovered a separate stellar system in M33 when he observed Cepheid variable stars.
These stars are used for determining the distance of other galaxies because they emit a constant brightness.
The Triangulum galaxy is hurtling toward the Milky Way at a breakneck speed of 62,000 mph/100,000 kph.
Some scientists theorize that the Andromeda galaxy has a gravitationally trapped Triangulum.
Triangulum Galaxy Formation
The Triangulum galaxy is a spiral galaxy with well-distributed dust, which has led scientists to suggest that there may never have been any interactions between the triangle and other galaxies.
To understand the spiral arms, astronomers study collisions and near misses. If these two events occur at just the right angle with each other, they can pull apart a galaxy’s spirals or even create new ones!
The Triangulum Galaxy is one of the newer members of our Milky Way group- but no one knows how old it is yet.
Triangulum Galaxy Structure
The Triangulum galaxy is the third-largest in the Local Group and it’s quite near to our own, at an inclination of 54°.
The stars are so far away that they appear warped out to a radius of about 8 kpc! It may have more than just one disk like ours does.
There could be multiple disks all around its galactic nucleus because most galaxies seem to share this feature (though we can’t confirm anything right now).
Triangulum is classified as an unbarred galaxy, but analysis of the shape shows what appears to be a weak bar-like structure about the galactic nucleus.
The extent of this radial structure is around 0.8 kpc and it may contain an ultraluminous X-ray source with emission at 1.2 × 1039 erg s−1 which makes up for one of the most luminous sources in our Local Group galaxies! This source has been observed to fluctuate by 20% over a 106-day cycle.
The Triangulum Galaxy may not have a supermassive black hole as the upper limit for its mass is 3,000 solar masses.
This means that there’s no evidence of a central black hole at all in this galaxy and makes it one of only two galaxies without an SMBH in our local group.
Despite being smaller than Andromeda or Milky Way, we can see stars moving much faster due to their proximity to us.
The Triangulum galaxy has two luminous spiral arms, along with multiple spurs that connect the inner to outer features. The main arm designated as “IN” is north and south are named accordingly.
