AST- 105 1st EditionLecture 11Outline of Last LectureI. SunspotsII. Solar Wind and EarthOutline of Current Lecture I. Solar NeutrinosII. Introduction to StarsCurrent Lecture I. Solar Neutrinosa. Neutrino- a very low mass, neutral particle that travels near the speed of lighti. Interacts very weakly with matterii. Created when a proton is converted into a neutron by nuclear fusioniii. Escapes directly from the Sun’s fusion zoneb. Detecting Solar Neutrinosi. Most neutrinos pass right through Earthii. Neutrino telescopes detect about 1/3 of the solar neutrinos originally predicted.1. This indicates that neutrinos oscillate between three different types:a. Electronb. Muonc. Tau2. Early neutrino detectors only can detect one type of neutrino3. Neutrino oscillations have been tested by MINOS experiment.4. Fewer muon neutrinos are received than emitted.a. This indicates that neutrinos oscillate. II. Introduction to Starsa. Parallax- the apparent shift of an object due to a change in viewpoint.i. Stellar Parallax (p)1. Full baseline is the diameter of Earth’s orbit2. P = ½ of apparent shift of star as Earth moves from one side of its orbit to the other3. Usually measured in arcseca. 1 arcsec = 1/3600 degreesb. 1 degree = 3600 arcsec ii. Distance of a star is calculated by the following formula:d = 1 / pp = parallax in arcsecd = distance in parsec1 parsec (pc) = 3.26 lightyearsiii. Distance varies inversely with parallax1. The larger the distance, the smaller the parallax2. At a distance of 1 parsec, a star has a parallax of 1
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