Many stars do not live alone. A binary star is a pair of stars bound by gravity, orbiting a common center of mass. Roughly half of Sun-like stars have at least one companion, and the share is higher for massive stars. Types by how we detect them Visual binaries: both stars can be seen separately … Read more
A white dwarf is the exposed core left behind when a star like the Sun runs out of fuel and sheds its outer layers. Roughly 97 percent of stars in the Milky Way, including the Sun, are expected to end as white dwarfs. Small, dense and hot A typical white dwarf has about half to … Read more
Stars are usually born in groups. A star cluster is a family of stars that formed from the same cloud at about the same time, so they share a similar age and chemical makeup. This makes clusters ideal laboratories for studying how stars evolve. Open clusters Famous examples: the Pleiades (the Seven Sisters), visible to … Read more
Every star is born in a cloud of gas and dust and spends its life in a balance between gravity, which pulls inward, and the pressure of nuclear fusion pushing outward. Its mass at birth decides how long it lives and how it dies. Birth in molecular clouds Stars form in cold, dense clouds of … Read more
Stars look like identical points of light, but they differ enormously in temperature, size, brightness and lifespan. Astronomers sort them with two simple tools: a letter for temperature and a Roman numeral for size. Spectral classes: sorting by temperature The Harvard system, developed in the early 1900s by Annie Jump Cannon and colleagues, groups stars … Read more
