Astronomy Unit 6 Exam - Questions & Answers

Astronomy Unit 6 Exam - Questions & Answers How can a white dwarf create a nova? A white dwarf that is part of a binary system can undergo repeated novas by consuming material from a main-sequence companion star. Describe the steps that the sun will follow for its evolution. Be able to draw its path on an H-R diagram. Nebula, Protostar, Main Sequence, Red giant, White Dwarf, Black Dwarf. (Up on the right, down, then up again til the middle of the graph, then slight down angle to the left, steeper downward angle to the right til the bottom center of the graph0 What are the primary differences between a Type-1 and Type-2 supernova? Type-1 When enough material has accreted, fusion can reignite suddenly, burning carbon. This results in a carbon explosion. Type-2 Enormous inward pressure due to high mass, collapses in a giant implosion, becoming more and more dense until protons and electrons react to become neutrons, collapse continues until neutrons recoil in supernova What does the singularity of a black hole refer to? A gravitation singularity at the center of a black hole, a point of infinite density What is the Schwarzschild radius? A circle around a black hole. Once a stellar remnant collapses within this radius, light cannot escape and the object is no longer visible. What is the event horizon? Imaginary spherical surface surrounding a collapsing star, with radius equal to a Schwarzschild radius, within which no event can be seen, heard, or known about by an outside observer. What characteristics can we use to distinguish between a stellar and a supermassive black hole? Stellar black holes have the mass of tmass of 100 Suns to a million. While Supermassive have a mass of a million to billions. How are pulsars created? Pulsars form when the core of a massive star collapses and goes supernova leaving behind a neutron star which will begin rotating and releasing energy. What is the "lighthouse factor"? When the poles of the pulsar face the Earth, it "blinks" on and off like a lighthouse What are the brightest and most distant objects in the known universe? Quasars