Transit method can measure a planets size from the amount of dimming of the

Transit method can measure a planets size from the

This preview shows page 2 out of 2 pages.

RV: can measure a planet’s minimum mass (from the amplitude of RV), but not its size. Transit method: can measure a planet’s size (from the amount of dimming of the star during transit), but not its mass. RV + transit: measure both mass & size! Follow-up RV on the Kepler planets: not easy. Most Kepler planets are far away & the host stars are dim → difficult to obtain the stars’ spectrum. photosphere: layer in solar atmosphere from which the sun’s visible light is emitted. opaque → cannot be anything below due to absorption of photons. solar granulation: granules form, disappear, reform for a few minute; 4m granules cover the solar surface. Solar energy early ideas: chemical energy & coal (can only last 10,000 yrs) or gravitational contradiction → could last 10 m yrs. answer: antiparticle every particle has a partner (e- → e+ & p → p-) when a particle meets an antiparticle, they annihilate each other & energy is released neutrino: a neutral weak particle; hard to detect & much smaller than electron energy transport. photons scatter & diffuse out to surface in 10^5 yrs. not efficient, lot of heat loss. solar neutrinos solar interior can’t be observed due to opacity but neutrinos can penetrate huge amounts of material w/out being absorbed. theory was questioned → made 3 different neutrinos; nuclear fusion produces v^e. different neutrinos can spontaneously convert into one another solar wind: charged particles from the solar atmosphere flows away from the sun. coronal holes: largely from sparse regions of corona. active sun → sunspots, prominences, solar flares, coronal mass ejections. sunspots are magnetic , dark because they are cooler than the surrounding gas. number of sunspots on the sun varies w/ a period of about 11 yrs. sun's differential rotation → solar activity. rotates faster at the equator than at high latitudes. magnetic field lines are twisted → sunspots form where kinks in magnetic field pop through the surface. 11 yr sunspot cycle = 22 yr magnetic cycle. prominences: magnetic looks can extend up into suns corona, gas from chromasphere can be trapped in the loops, cooler & denser than surround corona. how does solar activity affect humans: Bursts of charged particles from Sun can disrupt communications, satellites, & electrical power generation
Image of page 2

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture