Occurrence of 1-4 REarth Planets Orbiting Sun-Like Stars

Transcription

1 Occurrence of 1-4 REarth Planets Orbiting Sun-Like Stars Geoff Marcy, Erik Petigura, Andrew Howard Planet Density vs Radius + Collaborators: Lauren Weiss, Howard Isaacson, Rea Kolbl, Lea Hirsch Thanks to: UC Berkeley, Univ. Hawaii, Keck Observatory, NASA 1

2 Kepler Planets Jupiter R p / R e 4 Neptune 1 Earth Period [days] Rowe et al. (2014)

3 Kepler Planets Jupiter For a given stellar sample: R p / R e 4 Planet Occurrence = N(planets) N(stars) Neptune 1 Earth Rowe et al. (2014) Period [days] 3

4 Kepler Planets Jupiter R p / R e 4 Planet Occurrence = Neptune N(planets found) + N(planets missed) N(stars) 1 Earth Rowe et al. (2014) Period [days] 4

5 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

6 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

7 TERRA In-house photometric Transit Search: Optimized for small planet detection Enables measurement of detection efficiency (completeness) using injection and recovery experiments E.Petigura (2013)

8 TERRA optimized for small planets Time domain preprocessing - Start with raw photometry - Gaussian process detrending - Calibration - Petigura & Marcy 2012 Earth-size planet found Transit search - Matched filter - Similar to BLS algorithm (Kovcas+ 02) - Leverages Fast-Folding Algorithm (Staelin+ 68; Petigura+ 13, in prep) Data validation SNR = 30 - Significant peaks in periodogram, but inconsistent with exoplanet transit SNR (Kovacs, Zucker, Mazeh 2002) depth = 180 ppm Transit Periodogram P = 10.4 days Transit Period [days]

9 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

10 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

11 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

12 Identifying eclipsing binaries using secondary eclipses Flux Primary 7% dimming Flux (ppt) Secondary 0.2% dimming Teff = 2343 K not a planet Time (days)

13 40,000 bright GK stars Search for significant transits using TERRA photometric pipeline Q1 Q TCEs Remove non-astrophysical false positives 836 ekois Remove astrophysical false positives 603 planet candidates Centroid Odd-even Transit shape Secondary eclipse

14 603 Planet Candidates Planet size (Earth-radii) (95%) KOIs (Nov 2013) 597 (99%) KOIs (Jun 2014) Keck HIRES spectra of 318 ekois Keck Spectra of all 62 Stars Orbital period (days) Keck spectra of all 62 candidates with P > 100 days 14

15 Keck HIRES Spectra KIC Better stellar parameters - R good to 10% (photometry: 40%) KIC L good to 25% (photometry: 80%) Find false positives KIC Flux - Detect second set of lines - Kolbl and Marcy (2014) Wavelength (A) Petigura+ in prep (SpecMatch) 15

16 False positive vetting G Star + Earth G Star + M Star + Neptune Kolbl and Marcy (2014) 16

17 Representative Earth-size Candidates KIC P Rp 1.37 Fp 0.74 KIC P Rp 1.47 Fp No KOI KIC P Rp 1.73 Fp 1.57 Period > 40 days /10 are KOIs KIC P Rp 1.87 Fp 2.95 KIC P Rp 1.43 Fp KIC P Rp 1.65 Fp 1.98 Keck spectra of all Text Text KIC P Rp 1.48 Fp 2.93 KIC P Rp 1.74 Fp KIC P Rp 1.04 Fp Flux flux (ppm) KIC P Rp 1.95 Fp t - t0 [days] Time (days) Figure S15: Phase folded photometry for ten Earth-size HZ candidates. Black point shows show TERRAcalibrated photometry folded on the best fit ephemeris listed in Table S2. The green symbols show the 17

18 Planet Occurrence =??? N(planets found) + N(planets missed) N(stars)

19 Earth-size planet dims star by 0.01% Planet detected Brightness Time 1 year Does not transit Star too noisy 19

20 Injection and Recovery Determination: Pipeline Completeness Draw ( RP, P ) randomly from search domain Planet size (Earth-radii) Injected transit recovered Text not recovered 2. Choose random star from survey (40,000 GK stars) Survey Completeness (C) % 3. Inject synthetic light curve in photometry (real noise) 4. Execute TERRA pipeline 5. Did we recover the injected planet? Orbital period (days)

21 40,000 Injection and Recovery Experiments 40,000 Injection and Recovery Experiments 21

22 Completeness from Injection and Recovery 20 Planet size (Earth-radii) Survey Completeness (C) % Orbital period (days) Fig. 1 Two-dimensional domain of orbital period and planet size, on a logarithmic scale. Red circles show the dete planets in our survey of 42,557 bright, Sun-like stars (Kp =10 15mag,GKspectraltype). Thecolorscaleshowssu

23 Planet Occurrence = N(planets found) + N(planets missed) N(stars)

24 Planet Occurrence: Planet Size and Orbital Period 16 74% Planet size (Earth-radii) % 7% 6% 5% 4% 3% 2% 1% 0% Planet Occurrence Orbital period (days) 24

25

26 26% of GK stars have Planets: Radius: 1-2 R Earth Period: < 100 days

27 26% of GK stars have Planets: Radius: 1-2 R Earth Period: < 100 days

28 Batalha 26% of GK stars have Planets: Radius: 1-2 R Earth Period: < 100 days Mullally, Batlaha, Burke, et al: 29% for 1-2 REarth, P < 50 d 60% for 1-2 REarth, P < 300 d Charbonneau et al:

29 Batalha 26% of GK stars have Planets: Radius: 1-2 R Earth Period: < 100 days Mullally, Batlaha, Burke, et al: 29% for 1-2 REarth, P < 50 d 60% for 1-2 REarth, P < 300 d Charbonneau et al: Our work: Only one planet included per host star. ==> 26% is a Lower limit to occurrence

30 26% of GK stars have Planets: Radius: 1-2 R Earth Period: < 100 days

31

32 Planet Occurrence: Planet Radius and Incident Flux Planet size (Earth-radii) Survey Completeness (C) % Stellar Light Intensity (Earth-units) 32

33 Planet size (Earth-radii) ± 4% occurrence FP = 1 4 FE RP = 1 2 RE Spectroscopic Errors 1 2x Size of Earth Stellar Light Intensity (Earth-units) 33

34 Multi-Planet Sub-Neptunes: Formation Clue Orbital Distance (AU)

35 Multi-Planet Sub-Neptunes: Formation Clue Not in Mean Motion Resonances Orbital Distance (AU)

36 Multi-Planet Sub-Neptunes: Formation Clue Not in Mean Motion Resonances Inward migration in lock-step, and parking are both unlikely. Orbital Distance (AU)

37 Multi-Planet Sub-Neptunes: Formation Clue Not in Mean Motion Resonances Inward migration in lock-step, and parking are both unlikely. Sub-Neptunes formed nearly in situ. Orbital Distance (AU)

38 Sub-Neptunes: Summary Ü Probably Formed in close - Near where are they are now.