ASTR 151 1st Edition Lecture 31 Outline of Last Lecture I Chapter 14 1 II Chapter 14 2 Outline of Current Lecture III Chapter 15 Current Lecture I Chapter 15 a How our Universe was created i Condensation Theory 1 Interstellar cloud of gas contracts and begins to heat up 2 The star Sun forms in the center dust provides condensation nuclei 3 As planets form they sweep smaller debris in b Astrometry i Measuring a star s position in the sky and observes how the position changes over time 1 Was recorded by hand back in the day c 1st Exo planet Discovery i Early 1990 s orbiting a pulsar PSRB1257 12B d Kepler Mission i To search for planets smaller than Jupiter ii Planets in Formation 1 55 solar mass Red Dwarf 2 Possible planet 7 5 million miles out 3 Young star 8 million years old These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 4 Most star examined have planets a More stars in large orbits than small orbits b Big planets with small stars are called hot Jupiters iii How to detect them 1 Direct a Works for large planets usually that aren t closest to parent star 2 Indirect a Radial velocity Doppler b Gravitational Micro lensing i Gravitational field of a star or other large body magnifies light ii Good for planets far from parent stars c Transit Method i Measuring the dimming of a planet s light ii Relies on the relative sizes of star or planet iii Only works if the orbits are all aligned from point of view of observer iv False detections 1 Eclipses 2 Stellar variation d Transit time Variation e Newton s Law i F MsunMp1G r 2 f 3rd law of Kepler i p 2 a 3 constant g Doppler Spectroscopy Wobble i Looking at the parent star s emissionsvariations
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