1 Astronomy Planets Stars and Galaxies AST1002 Section 3 MW 1 25 Professor Andrew Askew STUDY GUIDE DEFINITELY 1 EXAM QUESTION ON EACH OF THE FOLLOWING Red Shift Blue shift Gravity Wein s Law Stefan Boltzman Law Jovian World Properties The Sun The 6 moons Internal Heating Roche Limit Electromagnetic Spectrum Absorption Emission Lines Sequence of Star Formation Light and Temperature 2 ALL QUIZES AFTER EXAM 1 Quiz 5 1 Three out of four of the Jovian Worlds exhibit some form of internal heating e q they radiate more energy then they observe from the Sun Which of the four does not URANUS 2 Why is Saturn measured to have a smaller magnetic field than Jupiter BECAUSE SATURN S INTERNAL LAYER OF LIQUID METALLIC HYDROGEN IS MUCH SMALLER THAN JUPITER S 3 Uranus and Neptune appear more blue than the other Jovians What gas in the atmosphere is responsible for this METHANE 4 Which of the four Jovian Worlds experiences extreme seasonal variations due to its unusual rotational tilt URANUS 5 If the Earth suddenly shrank to half its radius while its mass doubles what would happen to the force on you IT WOULD OCTUPLE x8 THE DISTANCE FROM THE MOTHER PLANET INSIDE WHICH A MOON WILL BE DESTROYED BY TIDAL FORCES Quiz 6 1 What is the Roche Limit 2 What are shepherd moons MOONS WHICH GUIDE MATERIAL IN RINGS INTO STABLE ORBIT 3 What is the cause of Io s volcanic activity CONSTANT TIDAL FORCES FROM JUPITER S AND EUROPA S GRAVITY 4 What is the primary component of Titan s atmosphere NITROGEN 3 Quiz 7 1 Which of these is the correct order of electromagnetic radiation in terms of increasing energy INFRARED VISBLE ULTRA VIOLET X RAY 2 Which of these is the correct order of magnitude for the temperature of the Corona 1 000 000 KELVIN 1 MILLION 3 What is absolute zero temperature THE TEMPERATURE AT WHICH ALL THERMAL MOTION STOPS 4 True of false Electrons in atoms may only occupy certain orbitals which correspond to discrete exact energy levels TRUE 5 The starship enterprise is radiating visible light It moves very quickly away from observers on the Earth How does the apparent wavelength of this light change THE WAVELENGTH APPEARS LONGER MAKING THE LIGHT APPEAR REDDER Quiz 8 1 What do we tend to refer to as the surface of the Sun PHOTOSPHERE 2 What is the correct order of magnitude for the temperature at the center of the Sun 10 000 000 KELVIN 10 MILLION 3 True or flase Sunspots appear dark against the rest of the Sun because they are relatively warmer than the rest of the surface FALSE 4 The radiation zone is A REGION OF THE SUN WHERE THE MATERIAL IS MAINLY IONIZED AND WHERE PHOTONS CAN TRAVEL THROUGH RELATIVELY FREELY 5 True or false The crushing pressure of the Sun s gravity is balanced by the internal pressure from the nuclear reactions occurring in the Sun s core TRUE Quiz 9 1 In terms of the spectral classification of stars what is the hottest O Oh Be a Fine Girl Guy 2 What inputs allow me to calculate the size of a star TEMPERATURE AND LUMINOSITY 4 3 True or false As few as two wavelength measurements in intensity can be used to estimate the temperature of a star TRUE 4 What is plotted on the Hertzsprung Russel H R diagram to clarify what are the x and y axes LUMINOSITY AND TEMPERATURE 5 True or false As the distance to an object in space increases the parallax angle also increases FALSE Quiz 10 1 Red Giants are LARGER AND COOLER THAN EARTH S SUN 2 What s is Helium Flash THE SUDDEN IGNITION OF HELIUM FUSION WHEN A STAR S TEMPERATURE BECOMES HOT ENOUGH AT THE CORE 3 What is the ultimate fate of our Star OUR STAR WILL BECOME A BLACK DWARF 4 If a star becomes simultaneously hotter and less luminous how does it move on the H R diagram DOWN AND TO THE LEFT 5 How much more mass would Jupiter have needed to become a star ABOUT 100 TIMES ITS MASS 5 Lecture 10 Gravity Jovian Characteristics JUPITER Gravity Things that have mass attract each other More mass greater the attraction If earth had 2x mass exert 2x the force including force on you Acceleration doesn t depend on mass Same acceleration rate of gravity for any object If earth has the radius the force would quadruple on you The greater the mass the greater the gravitational pull If EARTH were doubled in mass then your acceleration would double If YOU were doubled in mass then your acceleration would stay the same Jovian Planets Jupiter and further from the Sun We know less about these worlds Due to being farther out they receive less and less energy from the sun than terrestrials Widely spaced orbits large masses large radii predominantly gaseous faster rotation strong magnetic fields low density many rings and moons surface not solid Formed a lot like Terrestrials metallic rocky core However Jovians were fast enough that their gravity pulls in gas and dust directly from the solar nebula JUPITER Massive Strongest Magnetic field Rings not to the extent of Saturn Jupiter s rings are thought to be debris from meteor impact Atmosphere and Structure Hydrogen with little of helium and then others Surface of Jupiter Haze Layer layer that obstructs our view towards the center of Jupiter Magnetic field is so strong that it gathers enormous amounts of particles ton of energy Belts Zones Weather Structure Banded areas of Jupiter s atmos are described as lighter areas zones darker areas belts Bands different convective motion like Earth s Hi Lo pressures Underlying bands zones are zonal flows Great Red Spot Hurricane sustained by large scale atmospheric motion White Ovals High cloud tops that reflect light from Sun Brown Spots a break in the upper cloud layer allowing a look into lower atmosphere Hurricanes disrupts flow patterns that sustain storm FALSE not like Earth Not a solid surface so much as a different phase of the atmosphere goes from gaseous hydrogen to liquid to a metallic form surrounding the rocky core Under right pressure hydrogen assumes a state in which electrons dissociate from the protons Rapid rotation highly conductive fluid metallic hydrogen strongest planetary magnetic field Roughly a million times larger than Earth s and at the surface it s 14 times as strong Magnetosphere of Jupiter Internal Heating of Jupiter Jupiter is observed to radiate MORE energy than it receives from the Sun Atmosphere is so thick energy radiation still comes from initial formation Not from nuclear fusion Slowly leaking out THUS Jupiter was probably much warmer in the past Other ONLY slight equatorial tilt and a SHORT sidereal day about 10 hours 6 Lecture 11 JOVIANS