Behold the Triangulum Galaxy. It is, as the name suggests, a galaxy. It is categorized as a spiral due to its long arms circling outward around its center. It is the third largest galaxy in its group and is in the same group that our own Milky Way is a part of. Galaxies are thought to be formed by the long process of gravitational collapse of a large intergalactic cloud of gas. As it collapsed, the structure started spinning, increasing in speed as it decreased in size. Several of these clouds eventually collided and form the galaxies we see today. Within this condensing cloud, a similar process was occurring on a smaller scale creating the incomprehensible amount of stars we see today. The Triangulum was first discovered by Giovanni Battista Hodierna in 1654, but wasn’t distinguished as a spiral galaxy till 1850.
You can see many dark and light regions throughout the galaxy. There are denser areas of gas which has been given off in a nova by a dying star and has accumulated again by means of gravity. Dark nebula are dense enough to block out most all visible light and is the dominant visible nebula. The spiral arm structures suggest that the cloud from which the galaxy formed was less dense then that of a cloud that would have created an elliptical galaxy and had an original angular momentum which aided in its formation. This galaxy is divided into two regions which may be explained by an “inside-out formation” in which the inner region of the galaxy is has more older stars, and the outer region, formed by large gas accumulation later in the galaxies life, shows younger stars(Williams etal 2009). It has an atypical composition gradient that is flat instead of decreasing from the core (Magrini etal 2009). Based on the above image , the diameter of the Triangulum galaxy is approximately 16000 light years.
- Bonanos, A. Z. et al. (2006). "The First DIRECT Distance to a Detached Eclipsing Binary in M33". Astrophysics and Space Science 304, 207.
- Magrini, Laura; Stanghellini, Letizia; Villaver, Eva (2009). "The Planetary Nebula Population of M33 and its Metallicity Gradient: A Look Into the Galaxy's Distant Past". The Astrophysical Journal 696, 729–740.
- Fodera-Serio, G.; Indorato, L.; Nastasi, P. (1985). "Hodierna's Observations of Nebulae and his Cosmology". Journal of the History of Astronomy 16,1.
- Williams, Benjamin F.; Dalcanton, Julianne J.; Dolphin, Andrew E.; Holtzman, Jon; Sarajedini, Ata (April 2009). "The Detection of Inside-Out Disk Growth in M33". The Astrophysical Journal Letters 695, L15.
|Right Ascension (J2000)||01:34:32.10|
|Exposure time per filter||300 Seconds|
October 10, 2010
This image is a mosaic of four images placed to cover the large area of the Triangulum Galaxy.