Star HD 187123

Sun-like stars belong mainly to spectral type G and are commonly called yellow dwarfs. They have surface temperatures of roughly 5,300–6,000 K (about 5,000–5,700 °C), giving them a slightly yellow-white appearance. With masses typically between about 0.8 and 1.1 times that of the Sun, they sit between hotter, more massive white stars and cooler orange and red stars on the main sequence. The Sun itself is a standard G2V star and serves as the benchmark for understanding the structure and behavior of this stellar class.

These stars generate energy by fusing hydrogen into helium in their cores through the proton–proton chain. Their total lifetimes on the main sequence are around 10 billion years, during which their brightness slowly increases. After exhausting hydrogen in their cores, Sun-like stars expand into red giants, shed their outer layers to form planetary nebulae, and eventually leave behind dense white dwarfs. Many known exoplanet systems orbit Sun-like stars, making them key targets in the search for potentially habitable worlds.