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The basic unit of a chemical element. |
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A central part about which other parts are grouped or gathered. |
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subatomic particle with negetivly charged electricity.
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Subatomic particle contining a positive electrical charge.
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Subatomic particle with no electricity charge.
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Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei |
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How do thevarious elements differ from eacho other? |
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The atoms in different elements differ from the amount of protons, electrons and neutrons they contain. |
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The fixed amount of energy that a system described by quantum mechanics, such as a molecule, atom, electron, or nucleus, can have. |
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The lowest energy state of an atom or other particle. |
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Going from a higher energy level to a lower energy level (ground state)
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What is meant by blackbody radiation? |
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The electromagnetic radiation that would be radiated from an ideal black body; the distribution of energy in the radiated spectrum of a black body depends only on temperature |
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Features of the Blackbody Spectrum |
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1. The higher the temperature of the blackbody emitter, the higher the frequency (or shorter the wavelength) of the predominant light it emits
2. Hotter blackbodies give off a lot more energy than cooler blackbodies |
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A spectrum having no lines or bands, especially a spectrum of radiation distributed over an uninterrupted range of wavelengths. |
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Is said to have a discrete spectrum if it takes only distinct values, with positive gaps between one value and the next |
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A spectrum of the electromagnetic radiation emitted by a source. |
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Define absorbtion spectrum |
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A spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths.
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State Kirchoff's 3 laws and how emisson, absorbtion, and continuous spectrum are made from them. |
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Definition
1.A hot solid, liquid, or dense gas emits radiation at all wavelengths causing a continuous spectrum.
2.A thin hot gas in front of a cooler background emits radiation at a discrete set of isolated wavelengths causing emission lines
3.A thin cool gas in front of a hotter solid, liquid, or dense-gas background removes the radiation from the background source at special wave lengths causing absorbtion lines |
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a series of lines in the hydrogen spectrum |
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Note that hydrogen balmer lines are more pronounced in intermediate temperature stars. Why are they not present in hotter or colder stars? |
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1. If the cloud is too hot, the electrons in hydrogen have absorbed so much energy that they can break free from the atom. This is called “ionization,” and ionized hydrogen cannot create absorption lines because it no longer has an electron left to absorb any photons.
2. So, if the cloud of gas is too cool, the electrons will all be in the lowest energy level called the ground state and will have weak Balmer lines. |
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Note that other atoms and colecules, such as calcuim and titanium oxide also profuce absorption bands. Why is titanium oxcide only found in cooler stars? |
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Other stars are too hot for the molecules of Titanium Oxide to form. Titanium oxide is made of molecules; it is a chemical compound. If the star is too hot, atoms will get bashed into each other too hard for molecules to form.
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What is meant by the specteral classes: O, B, A, F, G, A, K, M |
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Classifying the stars from a sequence from hottest (O) to coolest (M)
The spectral class of a star is a short code summarising the ionizationstate, giving an objective measure of the stars temperature and density. |
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Stars temp by ranging from blue to red. Blue being the hottest and red being the coldest. |
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The change in the apparent frequency of a wave as observer and source move toward or away from each other |
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Recognize that when a star is approaching, its spectrum is __________ shifted toward smaller wavelengths, and that when it is receding its spectrum is _________ shifted toward longer wavelengths. |
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What are sunspots and how are they formed? |
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They form in cycles when the magnetic field bursts through the surface of the sun |
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The effect whereby the position or direction of an object appears to differ when viewed from different positions |
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When the distance is greater, the parallax is ____________ |
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What does the parallax say about the stars? |
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The more the stars move, the closer they are to Earth. |
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Define luminosity of the stars |
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luminosity measures the total amount of energy emitted by a star or other astronomical object per unit time. |
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How are HR diagrams related to the luminosity and temperature? |
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Temp: hottest to coldest (left to right)
Luminosity: dim-brightest (bottom to top) |
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Where are main sequence stars on the HR diagram?
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Diagonally across the diagram. This is where most of the stars lie. |
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Where do giant stars lie on the HR diagram? |
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at the very top middle of the diagram |
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Where do the red giants lie on the HR diagram? |
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above the main sequence on the very end by the cold temperatures. |
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Where do white dwards lie on the HR diagram? |
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below the main sequence in the hotter temperatures. |
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What is a visual binary system? |
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A visual binary system is a system in which two separate stars are visible through a telescope that has an appropriate resolving power. |
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What are spectroscopic binaries? |
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Spectroscopic binaries are systems in which the stars are so close together that they appear as a single star even in a telescope. |
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What is an eclipsing binary system? |
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A binary star whose components pass in front of each other, thereby causing a regular eclipse of one of the stars.
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What does a light curve show? |
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shows the brightness of an object over a period of time. |
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What are the more rare luminous stars? |
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the upper main sequence stars and the giants and supergiants. |
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What did Copernicus do for astronomy? |
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Proved that the sun was the centre of the solar system, and that the sun, earth and the moon were all shaped like round balls. He is often regarded as the starting point of current astronomy and the defining |
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What did Galileo do for Astronomy? |
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He Discovered that Earth was not the center of the solar system , Jupiter Has four moons and discovered the rings of Saturn. |
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What is Keplers Third Law? |
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