Science Chapter 11.1

Questions: How does a star birth? What is the evolution of stars? What are low mass stars? What are intermediate stars? What are high mass stars? Words to Know: black hole dopper effect fusion interstellar matter star supernova

Star: A celestial body of hot gases with a core like furnace that makes its own thermal energy Interstellar matter: The material that fills space, made up of gas(mostly hydrogen) and dust · dust counts only 1% of the total mass of all interstellar matter - small amount but makes it hard for astronomers to see like from distant stars · Interstellar - 'inter', 'stellar' means between stars Technology enabled astronomers to 'see' through the dusty curtains of interstellar matter, often called stellar nurseries Some telescopes -- e.g. radio and infrared are able to detect and record wavelengths of electromagnetic radiation that we cannot see with our eyes Star begins to form in nebula when gravity starts pulling + acting on chucks of gas and dust · gravity working = mass grows + material collapses it on itself and contracts · earliest phase of a star called "protostar"- proto means earliest · mass stays small = protostar may just shrink + never reach a full star status o · If it collects enough mass of dust + gas -> core will reach about 10 000 000 Celsius hydrogen atoms combine to form the heavier element, helium = whole process called nuclear fusion - this point, atoms fuse together to form a larger single atom o creates an enormous amount of energy · o when it reaches this stage, the star starts glow o hydrogen atoms combine to form the heavier element, helium = whole process called nuclear fusion