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| The main source of periodic solar variation driving variations in space weather.The cycle is observed by counting the frequency and placement of sunspots visible on the Sun. |
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| the state in the solar activity cycle where there are few sun spots and the activity of sunspots is low. also sunspots are further from the equator |
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| The Sun during the portion of its 11-year cycle in which sunspots, flares, prominences, and variations in radio-frequency emission reach their maximum. |
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| layer closest to the sun where the temperature is decreasing. this is also the visible surface of the sun. temp = 5,800 K |
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| transitional layer outside of the sun where the temperature starts in increase as opposed to decreasing. Above photosphere. temp = 4,500 K |
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| outer layer of the sun, outside transition layer (remember corona means crown in spanish), warmest layer where granulation occurs. temp = 1,000,000-3,000,000 K |
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when cells rise with heat and sink with lowering temperature on the corona.
in a graph: light=hot. dark=cold. |
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| A temporary disturbed area in the solar photosphere that appears dark because it is cooler than the surrounding areas. Sunspots consist of concentrations of strong magnetic flux. They usually occur in pairs or groups of opposite polarity that move in unison across the face of the Sun as it rotates. |
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| The darkest part of a sunspot |
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| the lighter area of a sunspot |
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| Plages are bright cloud-like features found around sunspots that represent regions of higher temperature and density within the chromosphere. |
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| How long is the lifespan of a sunspot? Sunspot groups? |
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Quiescent prominences arch-shaped, several hundred thousand kilometres long of relatively cool solar material that hangs nearly vertically to the Sun's surface for days or months.
It consists of a cloud of gas kept in position by the Sun's magnetic field and in the end may eject hot gas into the Solar System as a Coronal Mass Ejection (CME). |
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A prominence on the sun that is formed from active material above the chromosphere and reaches high altitudes on the sun at great speed
oops of magnetic fields with hot gas trapped inside. Sometimes, as the fields become unstable, the they will erupt and rise off of the Sun in just a few minutes or hours. If eruptions like these are directed toward the Earth they can cause a significant amount of aurora and other geomagnetic activity. |
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The wavelength at which a blackbody appears the brightest is inversely proportional to the temperature of the blackbody, i.e.,
W = 3x107/T(K) Angstroms, or T = 3x107/W K where 1 Angstrom = 10-8cm
tells us that objects of different temperature emit spectra that peak at different wavelengths.
Hot objects= short wavelengths & blue
Cool objects= long wavelenghts & red |
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The power radiated per unit area from a blackbody is proportional to fourth power of the temperature, i.e.,
Flux = constant x T4 |
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| A wind that is created when high temperatures on the corona evaporate off of the sun due to the massive amount of material and gravitational pull. |
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| regions in the corona that have been evacuated due to solar winds |
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Filaments are large regions of very dense, cool gas, held in place by magnetic fields. They usually appear long and thin above the chromosphere,
REMEMBER: Filaments and Prominences are the same thing, only prominences are coronal |
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| A sudden eruption of hydrogen gas on the surface of the sun, usually associated with sunspots and accompanied by a burst of ultraviolet radiation that is often followed by a magnetic disturbance. |
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| Classification of solar flares |
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Scientists classify solar flares according to their x-ray brightness in the wavelength range 1 to 8 Angstroms
X- Biggest
M-Medium
C-Smallest |
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| CME/coronal mess ejections |
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| Huge bursts of solar wind rising above the Sun’s corona. These are one of the biggest explosions in the Solar System |
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| effects of CMEs and flares on earth |
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| causes northern lights, can disrupt radio transmissions, cause power outages (blackouts), and cause damage to satellites and electrical transmission lines. |
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on the HR diagram these stars have a Strong correlation between Luminosity and Temperature.
Also, alternate definition of Main Sequence stars is that they are stars which are currently using hydrogen to helium fusion in their cores to supply their energy.
Information he randomly stuck on there:
problem?
Main Seqeunce stars are in equilibrium; both mechanical equilibrium (hydrostatic equilibrium -- stars are not changing in size very quickly) and thermal equilibrium (the temperature structures of stars are not changing very quickly -- the energy losses due to radiation and particles from stars are roughly balanced by the energy production due to nuclear fusion reactions).
Hotter stars are Brighter than cooler stars along the M-S.
About 85% of nearby stars, including the Sun, are on the M-S. |
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| Very large radius, but same masses as Main Sequence stars. giants, low density. supergiants, very low density. They are large, cool, and luminous. |
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| the more massive the stars the more luminous they are |
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| high density stars. Small, hot, and faint. |
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| Which two types of equilibrium do all main sequence stars obey? |
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| mechanical/hydrostatic Equilibrium and thermal equilibrium |
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| how can the sun create energy? |
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| chemical burning, nuclear reactions, and gravitational compression. |
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| how do main sequence stars usually generate energy? |
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| Main Sequence stars generates energy via the fusion of hydrogen into helium in its core |
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| Nuclear Energy Generation |
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| the conversion of 4 hydrogen nuclei into a helium nucleus + energy + other particles. |
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| the merging together of low mass nuclei into more massive nuclei. In the process, a little bit of mass may be converted into energy (Einstein's famous relation stating the equivalence of mass and energy, E=mc2 |
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| In the Sun, the energy is produced through the Proton-Proton Chain, the fusion of four hydrogen nuclei into a helium nucles, plus some other fundamental particles, and energy As a byproduct of the proton-proton chain reactions, a ghostlike particle known as the neutrino is also produced; several are produced every time an energy generating reaction occurs. |
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| Fission is the breaking apart of a massive nucleus into smaller nuclei and so is the inverse process of fusion |
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| Heisenberg Uncertainty Principle |
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| the Heisenberg uncertainty principle states that locating a particle in a small region of space makes the momentum of the particle uncertain; and conversely, that measuring the momentum of a particle precisely makes the position uncertain. |
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| Stars transport energy through.. |
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| convection and conduction. Also remember, heat moves from hot to cold |
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| Luminosity of a star of temperature T and radius R: |
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| Is star formation an ongoing process in our Galaxy? How do we deduce whether or not star formation is an ongoing process? Will the star formation process continue forever? |
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| yes, the amount of energy being released and destroyed, yes |
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| In which region of the Milky Way Galaxy does star formation occur? How do we deduce based on observations the locations of star formation in our Galaxy? |
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| The primary markers of star formation are H II regions (gas clouds of ionized hydrogen), O & B star associations and reflection nebulae, and the Giant Molecular Clouds (GMCs) |
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| What are the spiral arm tracers? |
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| Spiral arms are like compression waves which move through the disk of our Galaxy. |
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| In what kind of Interstellar Medium (ISM) cloud does star formation occur? |
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| it is roughly 90 % hydrogen and 10 % helium. The Ionized Hydrogen Clouds or region II is where the majority of star formation occurs. |
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| Asymptotic Giant Branch (AGB) Stars |
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| Region of the Hertzsprung-Russell diagram that lies above and roughly parallel with the red giant region. It is occupied by evolved stars of low to intermediate mass that have a dormant, helium-filled core surrounded by a helium-fusing shell, on top of which lies a hydrogen-fusing shell. These stars are large and red in color. |
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| A luminous shell of gas, often of complex structure, cast off and caused to fluoresce by an evolved star of less than about 4 solar masses. typically about 1 light-year in diameter. There is, however, quite a range of sizes due mainly to the fact that these objects expand with age. Majority of planetary nebulae occur near the plane of Milky Way. Greatest concentration near the galactic center, indicating that they're disc-shaped. |
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| Form from collapsing core of a massive star immediately following the star's exhaustion of its fusion energy reserves. Extremely small (smaller than white dwarf). Density roughly a million times that of white dwarfs. The higher the mass of a neutron star, the smaller its radius. |
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| Most Numerous Stars are... |
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| Different parts of the surface of the Sun rotate at different rates; the rotation period ranges from 27 days near its equator to more than 30 days near its poles. This uneven spin winds up the magnetic field lines of the Sun, same effect as one winds up a rubber band. As winding becomes tighter, the field is stressed. This leads to the formation of Sunspots, prominences, and an active corona. |
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| Why Nuclear Fusion is so difficult... |
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| There is competition between strong force and electrical force. When particles are far apart, the electrical force is much larger than the strong force. It is only when you get particles less than about a fermi apart that the strong force can overcome the effects of the electrical force and bind the nuclei together. Having to overcome the humongous electrical force between the positively charged nuclei (and its concomittant requirement of high temperature), forms the primary difficulty for nuclear fusion in stars and on the Earth. Particles often cannot overcome the electric repulsion b/c the electrical force is too large. |
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| It shows: As the activity level of the Sun increases the sunspots appear closer to the equator of the Sun. On a graph this makes a butterfly-like shape. |
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| period of extreme solar inactivity (sunspots) between 1645 and 1710, corresponded closely to "Little Ice Age" in Europe. |
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| Property of Sun that unites phenomena of the Solar Activity Cycle.. |
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| The magnetic field; the enhanced magnetic fields of sunspots, the arcade shapes of prominences, and the stored energy tapped by Solar flares. |
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| fusion reaction by which stars convert hydrogen to helium. Requires particles to overcome electric repulsion, takes average of 10^9 years to complete at temp of Sun's core. Cycle occurs slowly, which is why sun is still shining (or else it would have exhausted its hydrogen long ago). Occurs in stars the size of sun or smaller. |
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| Carbon-Nitrogen-Oxygen (CNO) cycle |
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| other fusion reaction where stars convert hydrogen to helium. Dominant source of energy in stars w/ greater mass than Sun. Four protons fuse using carbon, nitrogen and oxygen isotopes as a catalyst to produce one alpha particle, two positrons and two electron neutrinos . The positrons will almost instantly annihilate with electrons, releasing energy in the form of gamma rays. The neutrinos escape from the star carrying away some energy. Faster cycle than p-p cycle because its energy output increases faster in high temps. |
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| a matter particle and its anti-matter twin collide and are converted into energy (radiation) |
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| the maximum mass a white dwarf may have |
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| Energy transport mechanisms used by stars |
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| Conduction, Convection, and Radiative Transport |
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| What is the matter/anti-matter asymmetry problem? |
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| The Big Bang should have created equal amounts of matter and anti-matter, and all the matter and antimatter particles should have annihilated with each other since then, leaving only photons. But there was an imbalance early on in the universe, and now most of the universe is composed of matter. |
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| The properties of stars are determined by mass (most important) and chemical composition |
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