What scientific data do spectrographs primarily allow scientists to determine about a star by splitting focused starlight into its component wavelengths?
Temperature, chemical composition, density, and velocity
Spectrographs are considered arguably the most scientifically important tools attached to modern telescopes when studying the physics of stars. Their function involves taking the concentrated starlight and dispersing it, analogous to how a prism works, into its constituent wavelengths, creating a spectrum. By meticulously analyzing the unique pattern of dark or bright absorption and emission lines that appear within this resulting spectrum, astrophysicists gain critical insights into the star’s fundamental physical properties. These lines directly reveal the star’s current temperature, the specific elements present in its outer layers (chemical composition), its internal density, and its motion relative to the observer (velocity).
