Characteristics Used to Classify Stars:
* Temperature: Stars are categorized by their surface temperature, which determines their color. Hotter stars are blue, cooler stars are red, and everything in between. This is the basis of the spectral classification system (OBAFGKM).
* Luminosity (Absolute Magnitude): This refers to the star's intrinsic brightness, independent of its distance from Earth. Stars with higher luminosity emit more energy.
* Size (Radius): Stars come in a vast range of sizes, from tiny white dwarfs to massive supergiants.
* Composition: Stars are primarily composed of hydrogen and helium, but trace amounts of other elements influence their spectra.
* Mass: A star's mass is fundamental to its evolution and lifespan.
Characteristic NOT Used for Primary Classification:
* Distance from Earth: While distance is important for understanding a star's apparent brightness (how bright it appears from Earth), it's not used to classify the star itself. The classification is based on the star's inherent properties, not its position relative to us.
Think of it this way: A star is like a light bulb. You might classify bulbs by their wattage (luminosity), color (temperature), or size, but not by how far away they are from you.
