Astronomy Assignment: Stars and Stellar Evolution

Astronomy Assignment: Stars and Stellar Evolution Instructions: Answer the following questions with brief and clear explanations. Each question should be answered in 1-2 sentence. 1. Birth of Stars: a. How do stars form from molecular clouds? b. What is the role of gravity in star formation? 2. Main Sequence Stars: a. What characterizes a main sequence star? b. What type of nuclear fusion occurs in main sequence stars? 3. Red Giants and White Dwarfs: a. Why does a star become a red giant? b. What is a white dwarf? 4. Supernovae and Neutron Stars: a. What causes a supernova? b. How does a neutron star form? 5. Black Holes: a. How is a black hole formed? b. What is a key characteristic of black holes? _________________________________________________________________________ 1. Birth of Stars: a. Stars are born out of dusty molecular gaseous birthed matter primarily through gravitational compression of these birthed matter to form a protostar. b. Due to gravity, gas and dust in the cloud combine and start a collapse of the cloud and at the same time, the temperature rises until nuclear fusion starts. 2. Main Sequence Stars: a. A main sequence star can be defined based on the fact that the nuclear reactions which occur within it entails fusion of hydrogen into helium. b. Main sequence stars experience nuclear reactions at the core in which four hydrogen atoms fuse to from one helium nucleus. 3. Red Giants and White Dwarfs:Red Giants and White Dwarfs: a. When a star exhausts its hydrogen in the core it contracts and at the same time the outer layers expand making the star to become a red giant. b. A white dwarf is compact stellar remnant that is resulting from low to intermediate mass star that has expelled most of its mass. 4. Supernovae and Neutron Stars: a. I found that a supernova takes place as a result of exhaustion of the core of a massive star and its subsequent collapse. b. A neutron star evolve from the core of a supernova explosion. 5. Black Holes: a. A black hole is basically a region of space that exerts such a strong gravitational pull that nothing, not even light can escape from it and it is created after a supernova when a giant star dies and its core collapses in on itself. b. Black holes are somewhat extremely massive and when matter is packed tightly enough the gravity is so massive that even light cannot escape from it.