1.) which main-sequence stars on the hertzsprung-russell (h-r) diagram are the least massive? blue orange red yellow 2.) stars of which color have the highest surface temperature? red orange blue yellow 3.) neutron stars, smaller than white dwarfs, are thought to be remnants of supernova events red giants black holes nucleosynthesis 4.) another name for the interstellar matter that will eventually form a star is supernova red giant black hole nebula 5.) what theory states that the universe began in a violent explosion? big bang hubble’s law big crunch doppler effect