Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Astro Final part 4
| Question | Answer |
|---|---|
| The active sun and magnetic fields | The sun has magnetic fields. From a distance, it looks like a dipole field similar to the earth but up close it is much more complicated and active |
| The active sun | Sun rotates once every 24 days, 16 hours at equator. Once every 30 days at poles. Differential rotation, causes the magnetic fields to get tangled up and eventually break and reconnect |
| Tangled and broken magnetic fields cause | things like Sunspots, coronal loops, prominences, flares, coronal mass ejections etc |
| Flares and Coronal Mass Ejections | Matter thrown out into space (not returned to sun by magnetic fields like a loop) at up to 1500km/s (coronal mass ejections). Solar wind material will reach earth in 50 hours to cause aurora and communication disruptions |
| Solar wind | is deflected by Earth's magnetic field and atmosphere. Magnetic fields deflect wind particles to poles where they collide with the atmospheric molecules in the ionosphere causing the aurora |
| When ionosphere is disturbed during a flare | it makes communications difficult |
| How solar winds work | low flux or particles. Charged particles from sun hit field lines and move along field lines. Hit atmospheric particles, causes excitation then jumps down (causing emission) to cause green (blue is oxygen) |
| The Heliosphere | The sun's magnetic field extends far out into the solar system. Shielding us from Galactic cosmic rays. Heliopause and termination shock. Causes aurora on other planets in our solar system |
| Heliopause | The final boundary where the outward pressure of the solar wind is balanced by the inward pressure of the interstellar medium |
| Termination shock | The point where the solar wind, which has been traveling at supersonic speeds, suddenly slows down as it approaches the interstellar medium. The magnetic field strength increases significantly in this region |
| What planets have aurora | Jupiter, Saturn, Uranus |
| Solar structure and energy production in the core | The core is where the density ~10^5 times greater than sea level density and the temperature is >10^7 K. This temp is reached in the inner 20% of the radius. In the core the energy generated by fusion. NOT fission |
| Fusion | combines light nuclei into heavier ones thereby releasing energy |
| Sun is a big nuclear reactor | The mass of the two individual nuclei is more than the mass of the new atom. After the reaction there is some "missing mass" this mass is not destroyed but converted to energy via E=mc^2 |
| Proton-Proton Chain and the sun | is the most important reaction in the sun. The sun's energy output balances the force of gravity and keeps the sun in hydrostatic equilibrium |
| The rate of fusion is | temperature dependent. So small temperature instabilities/changes can have a dramatic effect on the energy production and, therefore, the structure (radius, density, pressure) of a star |
| proton-proton chain general | Needs temps>10^7K to move proton fast enough to slam into each other, overcome coulombic repulsion, and create fusion. We actually need quantum tunnelling |
| Step 1 of proton proton chain | 1H+1H->2H+(e+)+v |
| 1H | is ordinary hydrogen (1 proton, 1 electron, no neutrons) in reality the electron is ionized so this is JUST A PROTON |
| 2H | is deuterium (one proton, one neutron, one electron) in reality the electron is ionized so this is just a proton and neutron-a deuteron |
| e+ | is a positron or anti-electron (anti-matter) |
| v in proton proton chain | is a neutrino-no charge, tiny mass (1/10,000 of electron) move at almost speed of light |
| e- + e+ -> | y (gamma) Matter-antimatter annihilation. Also contributes to the energy |
| Proton-proton chain step 2 | 2H+1H->3He+gamma. The extra photon comes from the fact that the nucleus is formed in an excited state. It then spontaneously decays to a ground state and emits a photon |
| 3He | is helium 3 nucleus-2 protons, one neutron |
| Step 3 of proton-proton chain | 3He+3He->4He+H1+H1. Note that in core temps are so high that atoms are generally ionized |
| 4He | is a regular helium nucleus (aka an alpha particle) |
| So essentially in the proton-proton chain we are converting | 4 protons and 2 electrons into a helium 4 nucleus + energy + 2 neutrinos |
| What other term describes fusion | burning |
| Supergiants | 100 to 1000 R sun |
| Giants | up to 100 R sun |
| Brown Dwarfs | Jupiter size |
| White Dwarfs | Earth size |
| Neutron stars | 20km |
| Pulsars | 20km |
| Black holes | 10km |
| Photometry | Stars with different temperatures peak at different wavelengths. Or measure brightness at 2 different frequencies/wavelengths. Allows us to measure the brightness/flux of a star as well as its colour. (V and B filters) |
| Hottest to coldest stars | O, B, A, F, G, K, M. Oh be a fine gentleman kiss me |
| Temperature of O type star | 30,000K |
| Temperature of B type star | 20,000K |
| Temperatures of A type star | 10,000K |
| Temperature of F type star | 7000K |
| Temperature of G type star | 6000K |
| Temperature of K type star | 4000K |
| Temperature of M type star | 3000K |
Created by:
user-1996284