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IAU Symposium 276 -- Torino, 12 October 2010 Statistical patterns in ground-based transit surveys Andrew Collier CameronAndrew Collier Cameron University.

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Presentation on theme: "IAU Symposium 276 -- Torino, 12 October 2010 Statistical patterns in ground-based transit surveys Andrew Collier CameronAndrew Collier Cameron University."— Presentation transcript:

1 IAU Symposium Torino, 12 October 2010 Statistical patterns in ground-based transit surveys Andrew Collier CameronAndrew Collier Cameron University of St AndrewsUniversity of St Andrews SuperWASP Wide Angle Search for Planets TrES: The Trans-atlantic Exoplanet Survey

2 IAU Symposium Torino, 12 October 2010 Ground-based transit surveys STAREPSSTSLEUTH HAT XO HAT-SWASP

3 IAU Symposium Torino, 12 October 2010 Geographical distribution WASP-N(8) WASP-S(8) HAT-S(4) STARE(1) SLEUTH(1) PSST(1) HAT(2) XO(2) HAT(4) HAT-S(4) HAT(1)

4 IAU Symposium Torino, 12 October 2010 Typically ~ 5000 obs spanning 120N per seasonTypically ~ 5000 obs spanning 120N per season WASP observations per star

5 IAU Symposium Torino, 12 October 2010 Bright (V<14) Transiting planets

6 IAU Symposium Torino, 12 October 2010 Red noise and detection threshold Smith, A M S et al, nights 130 nights 80 nights 130 nights

7 IAU Symposium Torino, 12 October 2010 Orbital period distribution Orbital period in days Cumulative fraction

8 IAU Symposium Torino, 12 October 2010 Host-star apparent magnitudes V magnitude Cumulative fraction

9 IAU Symposium Torino, 12 October 2010 Host-star effective temperatures Bentley 2009, PhD thesis, Univ.of KeeleBentley 2009, PhD thesis, Univ.of Keele All dwarfs in WASP archive

10 IAU Symposium Torino, 12 October 2010 Smaller stars yield smaller planets

11 IAU Symposium Torino, 12 October 2010 Super-Jupiters & BDs With thanks to Magali Deleuil

12 IAU Symposium Torino, 12 October 2010 It isnt a planet until youve weighed it Magnitude range matches capabilities of RV spectrometers on 2-10m telescopes:Magnitude range matches capabilities of RV spectrometers on 2-10m telescopes: –OGLE: VLT8.2m/UVES –TrES: Keck10m/HIRES –HAT: OHP1.93/SOPHIE; SUBARU8.4/HDS –XO: McDonald2.7, HET11.0 –WASP-N: OHP1.93/SOPHIE, NOT2.4/FIES –WASP-S: Swiss Euler 1.2m, ESO3.6/HARPS

13 IAU Symposium Torino, 12 October 2010 Planetary mass-radius relation

14 IAU Symposium Torino, 12 October 2010 Host-star Metallicities [Fe/H] Frequency

15 IAU Symposium Torino, 12 October 2010 Fressin et al (2007)

16 IAU Symposium Torino, 12 October 2010 Fressin et al (2007)

17 IAU Symposium Torino, 12 October 2010 Gas-giant mass-radius relation

18 IAU Symposium Torino, 12 October 2010 Separation - Mass relation Mazeh, Zucker & Pont (2005)Mazeh, Zucker & Pont (2005) Low-mass gas giants avoid small separations.Low-mass gas giants avoid small separations. Ice-giants and super- Earths behave differently.Ice-giants and super- Earths behave differently. Symbol size denotes planet radius.Symbol size denotes planet radius.

19 IAU Symposium Torino, 12 October 2010 Irradiation - Mass relation Low-mass gas giants avoid strong irradiation.Low-mass gas giants avoid strong irradiation. Inflated planets found close to boundary.Inflated planets found close to boundary. –Symbol size denotes planet radius. Cf. Baraffe et al 2004Cf. Baraffe et al 2004 –Evaporation/expansion –Critical mass at radius a

20 IAU Symposium Torino, 12 October 2010 Irradiation-radius relation Guillot & Showman 2002Guillot & Showman 2002 Fressin et al 2007Fressin et al 2007 Symbol size denotes planet mass range:Symbol size denotes planet mass range: –Low: 0.0 to 0.5 M J –Mid: 0.5 to 2.0 M J –High: Above 2.0 M J

21 IAU Symposium Torino, 12 October 2010 Irradiation-radius relation Most apparent in restricted mass ranges.Most apparent in restricted mass ranges. Enoch et al 2010Enoch et al 2010 –0.1 M J < Mp < 0.6 M J –MNRAS, in press –arXiv/

22 IAU Symposium Torino, 12 October 2010 Tidal heating? Circles: WASP planets, RV onlyCircles: WASP planets, RV only Dots: WASP planets with low Lucy-Sweeney (1971) false-alarm probability.Dots: WASP planets with low Lucy-Sweeney (1971) false-alarm probability. Triangles: Upper limits on e cos from secondary- eclipse timing.Triangles: Upper limits on e cos from secondary- eclipse timing.

23 IAU Symposium Torino, 12 October 2010 Eccentricity versus K Poorly- constrained orbits yield spurious eccentricities.Poorly- constrained orbits yield spurious eccentricities. Lucy & Sweeney (1971)Lucy & Sweeney (1971) Laughlin et al (2005)Laughlin et al (2005) Ford (2006)Ford (2006)

24 IAU Symposium Torino, 12 October 2010 Why the prior increases with e e cos e sin

25 IAU Symposium Torino, 12 October 2010 Circularization timescale WASP planets with significant eccentricity detectionsWASP planets with significant eccentricity detections –Masses (M J ) in parentheses Triangles: Upper limits on e cos from secondary- eclipse timing.Triangles: Upper limits on e cos from secondary- eclipse timing. –Mostly less massive. Cf. Goldreich & Soter (1966):Cf. Goldreich & Soter (1966):

26 IAU Symposium Torino, 12 October 2010 Spin-orbit misalignments Measured via Rossiter-McLaughlin effect.Measured via Rossiter-McLaughlin effect. –Winn et al (assorted) Misaligned and retrograde planets surprisingly common: scattering/Kozai/tides?Misaligned and retrograde planets surprisingly common: scattering/Kozai/tides? –Triaud et al (2010); Wu & Murray 2003; Fabrycky & Tremaine 2007 Aligned planets more prevalent around cool stars?Aligned planets more prevalent around cool stars? –Winn et al 2010 See talks by Josh Winn, Amaury Triaud (Wednesday)See talks by Josh Winn, Amaury Triaud (Wednesday)

27 IAU Symposium Torino, 12 October 2010 Falling planets? Levrard et al 2008:Levrard et al 2008: Close-in planets lack sufficient orbital angular momentum to synchronize stellar spin to orbit.Close-in planets lack sufficient orbital angular momentum to synchronize stellar spin to orbit. Tidal evolution leads to spiral-in.Tidal evolution leads to spiral-in. See talk on WASP-18b and WASP-19b by David Brown, Thursday.See talk on WASP-18b and WASP-19b by David Brown, Thursday.

28 IAU Symposium Torino, 12 October 2010 Conclusions Ground-based surveys address the hottest gas- giant planets orbiting bright, ~solar-type stars.Ground-based surveys address the hottest gas- giant planets orbiting bright, ~solar-type stars. Mass-radius relationMass-radius relation –Low.mass planets: composition sequence –High-mass planets: radius anomaly appears to be primarily an irradiation effect. Orbital eccentricity distribution shows parameter dependences expected from circularization timescale.Orbital eccentricity distribution shows parameter dependences expected from circularization timescale. Spin-orbit alignment more common around stars with outer convective zones.Spin-orbit alignment more common around stars with outer convective zones. Some of the closest-orbiting gas giants may spiral into their host stars before the end of the main sequence.Some of the closest-orbiting gas giants may spiral into their host stars before the end of the main sequence.

29 IAU Symposium Torino, 12 October 2010

30 Host-star rotation - I Schlaufman 2010, ApJ 719, 602

31 IAU Symposium Torino, 12 October 2010 Eccentricity, mass, obliquity 21 planets with projected obliquity measurements21 planets with projected obliquity measurements –15 aligned –3 inclined, prograde –5 inclined, retrograde Orbital eccentricity Planet mass in M j Assorted works by Queloz, Winn, Wolf, Narita, Johnson, Bouchy, Hebrard, Cochran, Triaud, …

32 IAU Symposium Torino, 12 October 2010 Host-star rotation - II Schlaufman 2010, ApJ 719, 602

33 IAU Symposium Torino, 12 October 2010 Stellar rotation and tidal evolution For aligned systems:For aligned systems: Time to tidal spiral-in:Time to tidal spiral-in: –Hut 1980, 1981 –Dobbs-Dixon et al 2004 –Levrard et al 2009 Main-sequence lifetime:Main-sequence lifetime:

34 IAU Symposium Torino, 12 October 2010 Short life expectancies? For tidal dissipation factor Q=10 6 :For tidal dissipation factor Q=10 6 : Massive, eccentric planets have pseudo- synchronised host starsMassive, eccentric planets have pseudo- synchronised host stars t remain / t MS * / orb HD 17156b HAT-P-2b CoRoT-3b WASP-18b HD 80606b XO-3b

35 IAU Symposium Torino, 12 October 2010 Or inefficient tidal dissipation? For tidal dissipation factor Q=10 8 :For tidal dissipation factor Q=10 8 : t remain / t MS * / orb HD 17156b HAT-P-2b CoRoT-3b WASP-18b HD 80606b XO-3b

36 IAU Symposium Torino, 12 October 2010 Tidal evolution: WASP-18b Using tidal evolution prescription of Dobbs-Dixon, Lin & Mardling (2004)Using tidal evolution prescription of Dobbs-Dixon, Lin & Mardling (2004) 63 Myr 1 Gyr 2 Gyr 5 Gyr Hellier et al 2009 WASP-18 Hellier et al 2009

37 IAU Symposium Torino, 12 October 2010 Small stars yield small planets HAT/WASP/XO/TrES: median host-star T eff is close to solar.HAT/WASP/XO/TrES: median host-star T eff is close to solar. Small planets easiest to detect around smaller stars.Small planets easiest to detect around smaller stars. Survey volume contains few stars cooler than ~4600K.Survey volume contains few stars cooler than ~4600K. Long data trains and careful photometric extraction needed.Long data trains and careful photometric extraction needed. HAT-P-11b GJ436b Host Star T eff Planet radius in R Jup Cumulative probability

38 IAU Symposium Torino, 12 October 2010 Summary WASP detection thresholds comparable to HAT, TrES, XO.WASP detection thresholds comparable to HAT, TrES, XO. Bayesian candidate selection cuts down astrophysical false positives.Bayesian candidate selection cuts down astrophysical false positives. On-off photometry eliminates blended EBsOn-off photometry eliminates blended EBs Still room for improvement:Still room for improvement: –Lens temperature –DIA –Multi-season BLS. 16 planets found so far16 planets found so far –8 per hemisphere Interesting trends emerging!Interesting trends emerging!

39 IAU Symposium Torino, 12 October 2010 S. Aigrain (Cambridge -> Exeter) D. Anderson (Keele) S. Bentley (Keele) A. Carter (Open University) D.J. Christian (Belfast) W.I. Clarkson (Open University -> STScI) A. Collier Cameron (St Andrews) B. Enoch (Open University-> St Andrews) N.Gibson (Belfast) C.A. Haswell (Open University) L. Hebb (St Andrews) C. Hellier (Keele) K. Horne (St Andrews) J. Irwin (Cambridge -> CfA Harvard) Y. Joshi (Belfast) S.R. Kane (St Andrews -> Caltech) F.P. Keenan (Belfast) T.A. Lister (St Andrews/Keele -> LCOGT) P. Maxted (Keele) I. McDonald (Keele) A.J. Norton (Open University) J. Osborne (Leicester) N. Parley (Open University) D. Pollacco (Belfast) R. Ryans (Belfast) E. Simpson (Belfast) I. Skillen (ING) B. Smalley (Keele) A.M.S. Smith (St Andrews) I. Todd (Belfast) R.A. Street (Belfast -> LCOGT) R.G. West (Leicester) D.M. Wilson (Keele) P.J. Wheatley (Leicester -> Warwick) SuperWASP Wide Angle Search for Planets With: F. Bouchy (IAP) G. Hébrard (IAP) F. Pont (Geneva->Exeter) B. Loeillet (Marseille) M. Gillon (Geneva) M. Mayor (Geneva) C. Moutou (Marseille) F. Pepe (Geneva) D. Queloz (Geneva) A.M.H.J. Triaud (St Andrews -> Geneva) S. Udry (Geneva)

40 IAU Symposium Torino, 12 October 2010 WASP: stellar number density

41 IAU Symposium Torino, 12 October 2010 Systematics and red noise Systematics:Systematics: –Secondary extinction –Temperature-dependent focus –Sky brightness-dependent bias in background subtraction –SysRem: Tamuz et al 2005 –TFA: Kovacs et al 2005 Red noise:Red noise: –Pont et al 2006 –Smith et al 2006 RMS scatter RMS scatter (real data, 2.5-hr bins) RMS scatter (white noise, 2.5-hr bins)) RMS scatter RMS scatter (real data, 2.5-hr bins) RMS scatter (white noise, 2.5-hr bins))

42 IAU Symposium Torino, 12 October 2010 Planet-catch simulations Smith, A M S et al, 2006Smith, A M S et al, 2006 Besançon model:Besançon model: –V, T eff, [Fe/H] P(planet) = 0.03x10 2.0[Fe/H]P(planet) = 0.03x10 2.0[Fe/H] –Fischer & Valenti 2005 Linear CDF in log aLinear CDF in log a Transit probability ~ R * /aTransit probability ~ R * /a Inject fake Jupiter-sized planet transits into real WASP light curves.Inject fake Jupiter-sized planet transits into real WASP light curves.

43 IAU Symposium Torino, 12 October 2010 Red noise and planet catch Season 1 Season 2

44 IAU Symposium Torino, 12 October 2010 Sensitivity Transit depth threshold:Transit depth threshold: –0.01 –0.015

45 IAU Symposium Torino, 12 October 2010 Measurable parameters Winn 2008, IAU Symp. 253Winn 2008, IAU Symp. 253

46 IAU Symposium Torino, 12 October 2010 Measurable parameters Winn 2008, IAU Symp. 253Winn 2008, IAU Symp. 253


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