Stars are grouped according to their spectral characteristics by single letters of the alphabet, optionally with numeric subdivisions.

The seven main types of stars. How they’re classified and their roles in stellar evolution, lifecycle stages, and how they appear in the night sky.

Dec 18, 2025 · Scientists call a star that is fusing hydrogen to helium in its core a main sequence star. Main sequence stars make up around 90% of the universe’s stellar population. They …

Dec 4, 2025 · From hot stars to cool, the order of stellar types is: O, B, A, F, G, K, M. (A traditional mnemonic for this sequence is “Oh Be A Fine Girl [or Guy], Kiss Me.”) Additional letters have …

Feb 17, 2025 · Stars, the brilliant spheres of hot gas that light up the universe, come in many forms. From massive blue giants to faint red dwarfs, these celestial bodies are classified …

Using the letters O, B, A, F, G, K, and M, the 7 main types of stars are easily classified from hottest (O) to coolest (M). The temperature of each spectral class is then further subdivided …

May 3, 2025 · Along the way, we’ll explore the types of stars that fill our galaxy, their brilliant life cycles, and some astonishing facts that make stars among the most fascinating objects in all …

Aug 4, 2025 · Two factors result in so many different types of stars: the size of the clouds they are born from and what kinds of elements they contain. The Jewel Box Cluster (NGC 4755) is host …

Dec 6, 2024 · Astronomers classify stars into seven primary types, known as spectral classes, based on their temperature, color, and spectral characteristics. Here’s an overview of the …

O stars are the least common and M are the most common found in the main sequence of stars. Stars near the beginning or end of their lives are not part of this classification. The new system …