Astro MT 2 PDF

Essential physics - Light (300,000 km/s) - Spectral lines - Absorption lines: dark lines on a continuous rainbow spectrum.  - Emission lines: Colorful lines on a dark background. - Atomic Structure - Photons: Light is made...

Essential physics - Light (300,000 km/s) - Spectral lines - Absorption lines: dark lines on a continuous rainbow spectrum.  - Emission lines: Colorful lines on a dark background. - Atomic Structure - Photons: Light is made up of tiny packers of energy called photons, each photon has no mass and travels at the speed of light. - Primary regimes of the electromagnetic spectrum - UV: Shorter waves - Gamma: Shorter waves - IR: Longer waves - Radio: Longer waves - Blackbody radiation - Absorbs all incoming radiation - Spectrometer - Bohr model of the atom - Protons: Atomic Number - Neutrons: Mass subtracted from Atomic Number - Electrons: Same as protons - Forms of energy and conversion between them - Convection: Heat transfer in fluids - Radiation: Energy transmitted through electromagnetic waves - Conduction: Heat transfer through materials - Thermal: Energy that comes from heat of a substance - Gravitational: The higher the object, the more potential gravitational energy it has - Electromagnetic: Energy that travels in waves  - Nuclear: Energy stored in the nucleus of the atom, fission and fusion - Radiative energy: Energy emitted in the form of radiation The Sun - Spectral features - Solar flares - Coronal mass ejections - Sunspots - Prominences - The Corona - Solar wind - Different rotations: poles 35 days and equator 25 days - Magnetic field - Solar cycle - Abundances of elements - Mostly made up of hydrogen, then helium, and barely any heavier elements - Interior: zones and energy transfer mechanisms - Nuclear fusion at the core - Radiative energy transfer - Convective energy transfer - Core - - Radiative zone - --- Layer surround the core, energy transferred outwards by photons through radiative diffusion - - Convective zone - --- Outer layer of the sun's interior, energy is moved by the form of plasma, which rises to the surface, cools, then comes back down to be reheated, just like a lava lamp. - Atmosphere: regions and temperature structure - Photosphere - --- Visible surface of the sun, granules, sunspots, 5500K - Chromosphere - --- Solar prominences (loops of plasma), 4500K to 5000K - Corona - --- Visible during total solar eclipse, source of solar wind, 1 million K to 3 million K - Activity - Sunspots - Cooled down parts of the sun, about 3000K. It's still bright, however the surrounding the brightness makes it turn darkish - The solar cycle - Cycle for 11 years, phenomena such as solar flares, sunspots, etc. - Prominences - Loops of plasma that come out of the sun. It looks like a text message. - - Coronal mass ejections - Large explosions of the sun's corona, can travel millions of km into space - Energy generation and conversion - Nuclear reactions: fission and fusion - When atoms come together then split apart - Isotopes: notation and stability -   14 - C -   6 Stars - Measuring distances - Parallax - Color and temperature (Wien Displacement Law) - Lambda = b/T - Luminosity and temperature (Stefan-Boltzman Law) - L = oAT\^4 - Spectral types - Annie Jump Cannon's classification scheme: OBAFGKM - --- O is very hot (short wavelengths) - --- M is the coolest type (longer wavelengths) - Spectral features, atoms and molecules in atmospheres, and temperature - Hertzsprung-Russell Diagram - Properties on each axis - Regions:  - Main sequence: The stable phase of hydrogen burning in the cores of the stars. - Giant branch: When stars exhaust stars from their cores and leave sequence to become red giants. - White dwarfs: After shedding outer layers, stars like the sun evolve into these, which are hot remnants of stars that don\'t undergo fusion. - Evolution of Sun-like star on H-R diagram - Process of how stars become white dwarfs - Relationship between a star's color (temperature), luminosity, and radius - Color is determined by the surface temp - L = (R\^2)(T\^4) - Approximate locations of OBAFGKM stars on H-R diagram - - Star formation - Giant molecular clouds: Cold, dense regions of gas and dust where formation begins. - Collapse of molecular clouds: Can be caused by supernova or collision of clouds. As it becomes more dense, it collapses under its own gravity, then forms the star. - Relative numbers of stars formed by mass - M type stars - Stages of star formation - Molecular Cloud: Initial dense region - Collapse: Cloud collapses under gravity - Protostar formation: Protostar forms at the center - Accretion disk: Material forms a disk around the protostar - Main sequence star: Protostar ignites nuclear fusion - Stellar evolution - Sun-like stars - Stages of nuclear burning and their location - Hydrogen burning - main sequence, core - Helium burning - red giant phase, core - Heavier element burnings - Later stages, shells around the core - White dwarfs and planetary nebulae - Core becomes a white dwarf after a while - Outer layers of sun expelled forming nebula - Massive stars - Elements involved in nuclear burning - Hydrogen - fuses into helium - Helium - fuses into carbon and oxygen - Carbon - Fuses into heavier elements like neon, magnesium, and silicon. - End stages - Supernova - Huge explosion leading to black holes - White dwarfs - Gas cycle: stages and implications - Recycling material to create new stars