Lecture 11 Flashcards
What was so surprising about 51 Pegasi b, the first exoplanet detected by the RV method?
it had a surprisingly short orbital period of ~4 days
Which kind of planets were found most frequently by Kepler ?
Super-Earths (between 1.4 and 2.8 Earth radii)
What is so remarkable about the Trappist-1 planetary system?
It consists of seven Earth-size transiting planets in a compact orbital configuration
The results from NASA’s Kepler mission revolutionized our understanding of the exoplanet population. Which one of the following statements is incorrect?
Kepler discovered mostly hot Jupiters, so gas giant planets with orbital periods of just a few days
1st extrasolar planet around a sun-like star
51 Pegasi B (A hot Jupiter)
Summary of Exoplanet Properties from RV Studies
*~5-10% of normal solar-type stars have giant planets detected
* 0.5–1% of solar type stars have short period giant planets (hot Jupiters)
* Exoplanets have a wide range of orbital eccentricities (most are not in circular
orbits). This indicates a much moredynamicalpastthan for our Solar System!
* Many multiple systems, some in orbital resonances
* Close-in Jupiters must have migrated inwards!
* Current best RV precision allows detection of Earth-mass HZ planets around
low-mass stars (e.g. Proxima b)
Results from ground-based transit surveys
Transit probability ~10% for hot Jupiter
