Homework 5 (Jocelyn)


  • Astrometry 
    • Estimate the semi-major axis beyond which astrometry (orbit face-on) becomes more sensitive than radial velocity searches (orbit edge-on).
  • Exoplanet Phase Variations
    • What is the maximum phase amplitude we would observe for the planet?
    • What eccentricity will produce the same maximum phase amplitude as that calculated from part (a)?



  • Exoplanet Demographics 
    • What were two early surprising features of exoplanetary systems?
      • Ultra short period planets and Super Earths 
    • What correlation of planet size with occurrence have Kepler results demonstrated?
      • The planetary radius gap is real
    • How is the Habitable Zone around a star define?
      • It is the region around a star which Earth like planet can possess liquid water on its surface 
  • Stellar Parameters 
    • For a typical star with uncertainties of 10% for both the mass and radius, what does this imply for the uncertainty in the mass and radius of the planet?

  • Planet Formation
    • What are two properties of a proto-planetary disk that determine the kinds of planets that will form.
      • It is temperature and initial mass of the disk 
    • Describe the three basic types of planetary migration. 
      • Type 1: Occurs when the mass of the planet is small enough that the basic structure of the proto-planetary disk is not affected by the migration of the planet. The interaction is associated with spiral wave disturbances 
      • Type 2: Occurs when the mass of the planet is large enough to affect the basic structure of the proto-planetary disk. There is a gap in the disk, where the planet is as a result of the migration
      • Type 3: It is similar to type I migration, in that there are no changes to the basic structure of the proto-planetary disk. However this migration is faster. This interaction is associated with co-rotational flows in the disk. 
  • Planet Atmospheres 
    • What is meant by an “inversion layer” and why it is important for exoplanet atmospheres
      • The inversion layer is a departure from the usually decrease/increase with altitude of the value of an atmospheric property. It the atmospheric property is temperature, it can be useful to the exoplanet. This temperature inversion occurs on Earth due to ozone. The ozone in the stratosphere absorbs much of the sun's ultraviolet radiation, protecting the biosphere and warming up the stratosphere. 
    • Consider the atmospheric pressure at the summit of Mount Everest (elevation of 8.8 km above sea level). The Earth’s atmospheric scale height is 8 km. Calculate the altitude needed to reach the same atmospheric pressure on a super-Earth with a = 0.2 AU, Mp = 5M⊕, Rp = 1.2R⊕, and is orbiting a solar analog. Assume the surface pressure on the planet is the same as the surface pressure on Earth 


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HW5 Q2, Q3, Q5 (William Matzko)

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HW5 Q1 (William Matzko)

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