Study Guide For Chapters 16-19
Study Guide For Chapters 16-19 ASTR-1020-90
Popular in Stellar and Galactic Astronomy
verified elite notetaker
Popular in Science
This 0 page Study Guide was uploaded by Hannah Moore on Thursday March 17, 2016. The Study Guide belongs to ASTR-1020-90 at Clayton State University taught by Dr. Campbell in Winter 2016. Since its upload, it has received 22 views. For similar materials see Stellar and Galactic Astronomy in Science at Clayton State University.
Reviews for Study Guide For Chapters 16-19
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/17/16
Study Guide For Chapter 1619 Where do stars form 0 Stars form in dark dusty clouds of molecular gas with temperatures of 1030 K 0 These clouds are made mostly of molecular hydrogen H2 but stay cool because of emission by carbon monoxide CO Why do stars form 0 Stars form in clouds that are massive enough for gravity to overcome thermal pressure and any other forms of resistance 0 Such a cloud contracts and breaks up into pieces that go on to form stars What slows the contraction of a star forming cloud 0 The contraction of a cloud fragment slows when thermal pressure builds up because infrared and radio photons can no longer escape What is the role of rotation in star birth 0 Conservation of angular momentum leads to the formation of disks around protostars How does nuclear fusion begin in a newborn star 0 Nuclear fusion begins when contraction causes the star39s core to grow hot enough for fusion What is the smallest mass a newborn star can have 0 Fusion will not begin if a force stops contraction before core temp rises above 107K Degeneracy pressure stops the contraction of objects What are the typical masses of newborn stars 0 Star formation makes many lower mass stars than highmass stars How does a star39s mass affect nuclear fusion 0 A star39s mass determines its core pressure and temperature and therefore determines its fusion rate 0 Higher mass stars have hotter cores faster fusion rates greater luminosities and shorter lifetimes What are the life stages of a lowmass star Lilli Emile of a Star H White Aggie WEI Hedi Elia ifi il Fill fret r5 He hull 7 e Neutron Elin Elie llil if He hull M55 ier Eli r Em Ermine rhou J g A 1 1 711 I it Snipe rxgala ifiill Black quotWe H fusion in core main sequence H fusion in shell around contracting core red giant He fusion in core horizontal branch 0 Doubleshell burning red giant 0 How does a lowmass star die 0 Ejection of H and He in a planetary nebula leaves behind an inert white dwa What are the life stages of a highmass star 0 Protostar Blue mainsequence Red Supergiant HeliumBurning Supergiant Multiple shellburning supergiant COO 0000 0 nonburning hydrogen hydrogen fusion helium fusion inert carbon fusion iron core oxygen fusion neon fusion magnesium fusion sillioon fusion 2010 Pearson Education Inc Supernova o Neutron Star or Black hole How do highmass stars make the elements necessary for life 0 Higher masses produce higher core temperatures that enable fusion of heavier elements How does a highmass star die 0 Iron core collapses leading to a supernova How does a star39s mass determine its life story 0 Mass determines how high a star39s core temperature can rise and therefore determines how quickly a star uses its fuel and what kinds of elements it can make How are the lives of stars with close companions different 0 Stars with close companions can exchange mass altering the usual life stories of stars What is a neutron star 0 A ball of neutrons left over from a massive star supernova and supported by neutron degeneracy pressure How were neutron stars discovered o Beams of radiation from a rotating neutron star sweep through space like lighthouse beams making them appear to pulse 0 Observations of these pulses were the rst evidence for neutron stars What can happen to a neutron star in a close binary system 0 The accretion disk around a neutron star gets hot enough to produce x rays making the system an xray binary o Steady hydrogen fusion on surface producing a helium layer on the surface 0 Sudden helium fusion events periodically occur on a the surface of an accreting neutron star producing xray bursts What is a black hole 0 A black hole is a massive object whose radius is so small that the escape velocity exceeds the speed of light What would it be like to visit a black hole 0 You can orbit a black hole like any other object of the same mass 0 Near the event horizon time slows down and tidal forces are very strong Do black holes really exist 0 Some xray binaries contain compact objects too massive to be neutron stars 0 they are almost certainly black holes Where do gammaray bursts come from 0 Most gammaray bursts come from distant galaxies 0 They must be among the most powerful explosions in the universe probably signifying the formation of black holes What causes gammaray bursts 0 At least some gammaray bursts come from supernova explosions What does our galaxy look like 0 Our galaxy consists of a disk of stars and gas with a bulge of stars at the center of the disk surrounded by a large spherical halo How do stars orbit in our galaxy 0 Stars in the disk orbit in circles going in the same direction with a little upand down motion 0 Orbits of halo and bulge stars have random orientations How is gas recycled in our galaxy 0 Gas from dying stars mixes new elements into the interstellar medium which slowly cools making the molecular clouds where stars form 0 Those stars will eventually return much of their matter to interstellar space Where do stars tend to form in our galaxy 0 Active starforming regions contain molecular clouds hot stars and ionization nebulae 0 Much of the star formation in our galaxy happens in the spiral arms What clues to our galaxy39s history do halo stars hold 0 Halo stars are all old with a smaller proportion of heavy elements than disk stars indicating that the halo formed rst How did our galaxy form 0 Our galaxy formed from a huge cloud of gas with the halo stars forming rst and the disk stars forming later after the gas settled into a spinning disk What lies in the center of our galaxy o Orbits of stars near the center of our galaxy indicate that it contains a black hole with 4 million times the mass of the Sun
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'