Recognize the distance the stars are from Earth. The sun is the closest star at 93 million miles away from the Earth, while other stars such as Proxima Centauri are at least 6 trillion miles away from Earth. Since the sun is the closest to Earth it shines brighter than any other star.
Compare the colors of the stars with the sun. The sun is yellowish-white. If it were cooler, it would be red. Other stars are colored blue, blue-white, red, orange or yellow. For example, star Rigel is blue and star Proxima Centauri is red.
Check how hot or cool the stars are. The sun is considered a warm star at more than 9,000 degrees on the surface, hotter towards the core. Other stars are hotter, ranging from 15,000 to 70,000 degrees. A few are cooler, from 4,900 degrees to 7,200 degrees. Blue colored stars are the hottest stars, followed by blue-white, orange and yellow stars being a little cooler. Red stars are at the coolest temperature.
Notice the size of the stars. The stars range in size from supergiant to dwarf. The sun is considered dwarf size in comparison to most other stars. Supergiant stars are several hundred times larger than the sun, while giants are more common and are up to 100 times larger than the sun. Some stars are small in size being no larger than Asia. They are called white dwarfs.
Figure out the age of the stars. Depending on the color and rotational speed of the star will give an estimation on how long the star has been around. You can also determine the age of a star by the size. For instance, the sun is dwarf size, making it almost 5 billion years old.
