What are the differences between asterisms, constellations, and clusters?
This is what I have so far:
Constellations are patterns made up of stars. It has all the stars there to make up the pattern. Asterisms do not have complete patterns.
You are on the right track! Let me explain further:
1. Constellations: Constellations are groups of stars that form recognizable patterns or shapes when viewed from Earth. They serve as a way to organize the night sky and help astronomers locate specific celestial objects. There are 88 official constellations recognized by the International Astronomical Union (IAU). A constellation typically consists of numerous stars, and each star contributes to forming the overall pattern. Examples of constellations include Orion, Ursa Major (Big Dipper), and Scorpius.
2. Asterisms: Asterisms are also patterns formed by stars, but they are subsets or smaller groupings within a constellation. In other words, an asterism is a part of a constellation. Often, these subsets or smaller groupings within constellations are more well-known and recognizable to the general public than the entire constellation itself. For instance, the Big Dipper (part of Ursa Major) and the Summer Triangle (part of various constellations) are both examples of asterisms. Not all constellations have asterisms associated with them.
3. Star Clusters: Star clusters are groups of stars that are physically related and gravitationally bound. They are often located within constellations. Star clusters come in two main types: open clusters and globular clusters. Open clusters usually contain young stars that are formed from the same molecular cloud. They tend to have a looser, more scattered appearance. On the other hand, globular clusters are composed of very old stars that are tightly packed together in a spherical shape due to mutual gravitational forces. These clusters often appear as bright spherical objects in the sky. Examples of star clusters include Pleiades (an open cluster in the constellation Taurus) and M13 (a globular cluster in the constellation Hercules).
In summary, constellations are complete patterns made up of stars, asterisms are subsets or smaller groupings within constellations, and star clusters are groups of stars that are physically related.