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Courtney Dressing Advisor: David Charbonneau All Souls College, Oxford July 4, 2011.

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Presentation on theme: "Courtney Dressing Advisor: David Charbonneau All Souls College, Oxford July 4, 2011."— Presentation transcript:

1 Courtney Dressing Advisor: David Charbonneau All Souls College, Oxford July 4, 2011

2  Number of target stars: 156,453 (58,041)  Number of candidates: 1,235 (438) ◦ Orbiting 997 (375) stars Solar Subset: T eff = K log g = Kepmag < 15 Bright Dwarf Sample: T eff = K

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4  Within each grid cell, calculate: ◦ Number of candidates ◦ “Augmented” number of candidates ◦ Number of stars searched ◦ Planet occurrence rate

5  Number of non-transiting planets with same radius and period as transiting candidates =probability of transit where

6  Number of stars for which each transiting planet has SNR > 10

7 # of Stars Searched Augmented # of Planets Planet Occurrence Rate =

8  Periods <50 days  Radii: 2-32 R Earth

9 Planet Radius 10 Days17 Days 2 R Earth 2.8 R Earth Period

10 k R = /-0.4 α = ± 0.11

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12 Larger planets have shorter cutoff periods and sharper transitions.

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14 f 0 = 0.165±0.011 k T =-0.081±0.011

15  Random errors? ◦ Trend preserved for T eff = K ◦ Trend preserved after Monte Carlo applying gaussian random deviates to T eff and log g  Systematic stellar radius bias? ◦ Would require log g error of 1.6 dex ◦ Errors in KIC are ~0.25 dex  Systematic metallicity bias? ◦ Errors on [Fe/H] in KIC are ≳0.2 dex (rms) ◦ Cannot be ruled out

16  More massive planets have more H/He gas  Change at 4.5 M E ? Models from Fortney et al Solar system Kepler Other surveys

17  Assume planets with densities above 4 g/cm 3 are primarily composed of refractory elements

18  Toy density models ◦ Constant density ◦ Piece-wise constant density  Compared to Eta-Earth Survey ◦ Volume-limited survey of 166 GK dwarfs ◦ 35 planets detected around 24 stars ◦ Keck-HIRES ◦ See Howard et al. 2010

19  Black: Kepler prediction  Red: Eta-Earth measurement Decreasing density

20  Best models have ρ≳4g/cm 3 for Rp≲3R E

21  Planet occurrence increases with decreasing radius and increasing orbital period  Smaller planets (2-4 R E ) are more common around cooler stars (metallicity effect?)  Larger planets have steeper cutoffs at shorter periods than smaller planets  There is a ridge of high planet occurrence from 3 days and 2 R E to 50 days and 4 R E.

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