AST 105 1st EditionExam # 1 Study Guide Lectures: 1 – 9Lecture Highlights Prior to Quiz 1Kelvin: the absolute temperature scale used by astronomers and physicistsGalileo: the first individual to determine the rotation rate of the sun by watching the movement of sunspotsSurface temperature of the sun: 5800K Lecture Highlights Prior to Quiz 2 The net (effective) Proton-Proton Chain starts with four protons (hydrogen nuclei) and through fusion processes ultimately produces energy and one helium nucleus.Today, in many universities, astronomy is considered a subfield in the department of physics.The force that binds together particles due to their mass is gravity.The force that binds the electrons to the protons is electrometric.Lecture Highlights Prior to Quiz 3The theory of the duality of light: sometimes light acts like a wave and other time light acts like a particle. White light contains most (or all) of the colorsAn electromagnetic wave with a long wavelength must have a low frequency James Maxwell: scientist; the 4 fundamental equations that govern the classical(non-quantum) behavior of light Lecture Highlights Prior to Quiz 4 Stellar evolution: the study of the lifecycle of starsWe can obtain the total mass of a binary star system if we know the distance between the (semi-major axis) two and the orbital period.The highest surface temperature stars emit colors mostly of blues and purples.D=3.26 /θ- Absorption Spectrao A spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths - Astronomyo The branch of science that deals with celestial objects, space, and the physical universe as a wholeo Many universities, subfield of physics - AUo Astronomical unit, Earth’s distance from the sun (about 150 million kilometerso Commonly describe distances within our solar system in AU- Blackbody Radiatoro Also known as thermal radiationo The spectrum of radiation produced by an opaque object that depends only on the object’s temperature (an object that absorbs all incoming radiation and re-emits it in a pattern related to the object’s temperature o Two laws of blackbody radiation: the Stefan-Boltzmann law and Wien’s Law- Blueshifto A Doppler shift in which spectral features are shifted to shorter wavelengths, observed when an object is moving toward the observer - Chromosphereo Gives off U.V. Rayso Temperature is about 10,000 Kelvin- Coronao Outermost layer of the suno Temperature of about 10^6 Kelvino Gives off X-rays- Distance-Luminosity Relationo If you know distance (d) and apparent magnitude (m) you can find the luminosity(L) of a staro distance = Sq. Root (luminosity) / [4(pi)*(apparent brightness)]- Doppler Effect: o the change in frequency of a wave based on a persons location and movement. - Duality of Lighto light behaves like a particle and a waveo the particle of light is photon- Electromagnetic (EM) Spectrumo The complete spectrum of light, including radio waves, infrared light, visible light, ultraviolet light, X rays, and gamma rayso Order: Gamma rays, X rays, Ultraviolet light, Visible light, Infrared light, and Radio Waveso Left side of spectrum=shortest wavelengho Right side of spectrum= Longest wavelength o The shorter the wavelength the larger the frequencies- Energy (per atom) of Chemical Reactionso 10^-19 joules- Energy (per atom) of Nuclear Reactionso 10^-12 joules (10^7 x 10^-19)o Nuclear reaction is 10 million times greater than a chemical reaction - Galileoo The 1st to determine the rotation rate of the sun by watching the movement ofsunspotso Perfected telescope- Giantso Typically have a radius that is 10 to 100 times larger than the radius of the suno Including supergiants, account for 1% of all starso Cooler temp but high luminosity which means they must be very big- Hertzsprung and Russell and the H-R Diagramso Noticed relation between the stars’ surface temps and luminosityo Stars with high surface temps generally have large luminosities - Isaac Newton o first to explain that white light is composed of all colors (1670)- James Maxwello The four fundamental equations that govern the classical (non-quantum) behavior of light bear this scientist’s name- Kelvin and Helmholtzo Kelvin is an “absolute scale”, 0K is absolute zero aka particles stop movingo Suggested that the source of energy is gravitational collapses that produce chemical reactions that give off heat (energy)- Keplers Third Law (used to find mass sum of binary)o Ma+Mb= a^3/p^2 (mass of star a + mass of star b= distance^3/orbit period^2)- Luminosity (Absolute Magnitude)o Apparent brightness of a celestial body- Magnitude (Absolute and Apparent)o Apparent Magnitude (m): How bright a star appears from Earth without putting into account the distance of that star from Earth Brightest stars: m=1 Dimmest stars (visible to unaided eye): m=6 m=1 star is 100 times brighter than m=6 staro Absolute Magnitude (M): How bright a star actually is, this accounts for the distance the star is from Earth Move each star a distance of 1 PC (parsec) from Earth Brightest stars: M=-10 Dimmest stars: M=+17- Main-Sequence Staro 91% of stars. they can range from low temp and high luminosity to high temp and low luminosity. - Max Planck and his Constanto Planck’s constant: 6.63 x 10^-34 joules per second o Planck’s Law: Energy of a photon is equal to planck’s constant multiplied by the speed of light, all divided by the wavelength of a photon in meters - Multiplying Large Numberso Add exponents. o Example: 10^3 x 10^2 = 10^5 - Neutrino Flavors/Typeso there are 3 different types. (Ve, Vu, Vt)o A neutrino can change types as they travel in space. Ray Davis’s experiment only detected Ve type- Niels Bohro Modern Theory of the Atom (1920)o Energy is conserved, photons have energy. When an electron loses energy, itis equal to the amount that photons carry away. When an electron circles the nucleus of an atom, it will drop to a lesser orbit when a photon carries away energy (emission). When a photon carries in energy, the electron will expand its orbit (absorption). o Bohr’s Law- Orders of Magnitudeo The exponent indicated with sigma o Example: 10^2 = (sigma symbol) 2 - Photometryo One method of analyzing light from distant stars, the other is spectroscopyo Intensity of starlight at 3 different wavelengths are compared to the black body intensity curves, then a “best fit” will give us the surface