ASTR 151 1st Edition Lecture 31 Outline of Last LectureI. Chapter 14. 1II. Chapter 14. 2Outline of Current LectureIII. Chapter 15Current LectureI. Chapter 15a. How our Universe was created?i. Condensation Theory1. Interstellar cloud of gas contracts and begins to heat up2. The star (Sun) forms in the center, dust provides condensation nuclei3. As planets form, they sweep smaller debris inb. Astrometryi. Measuring a star`s position in the sky and observes how the position changes over time1. Was recorded by hand back in the dayc. 1st Exo-planet Discoveryi. Early 1990`s-> orbiting a pulsar (PSRB1257+12B)d. Kepler Missioni. To search for planets smaller than Jupiterii. Planets in Formation1. 55% solar mass Red Dwarf2. Possible planet 7.5 million miles out3. Young star 8 million years oldThese 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 planetsa. More stars in large orbits than small orbitsb. Big planets with small stars are called “hot Jupiters”iii. How to detect them:1. Directa. Works for large planets usually that aren`t closest to parent star2. Indirecta. Radial velocity (Doppler)b. Gravitational Micro-lensingi. Gravitational field of a star or other large body “magnifies” lightii. Good for planets far from parent starsc. Transit Methodi. Measuring the “dimming” of a planet`s lightii. Relies on the relative sizes of star or planetiii. Only works if the orbits are all aligned from point of view of observeriv. False detections1. Eclipses2. Stellar variationd. Transit time Variatione. Newton`s Lawi. F=(MsunMp1G)/(r^2)f. 3rd law of Kepleri. p^2/a^3=constantg. Doppler Spectroscopy (Wobble)i. Looking at the parent star`s
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