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SKARPS: the Search for Kuiper-‐Belts Around Radial-‐Velocity Planet Stars

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SKARPS: the Search for Kuiper-‐Belts Around Radial-‐Velocity Planet Stars SKARPS: the Search for Kuiper-belts Around Radial-velocity Planet Stars Geof Bryden, John Krist (JPL), Karl Stapelfeldt (Goddard), Chas Beichman (NExScI), Carlos Eiroa, Jonathan Marshall (Madrid), Amaya Moro-Martin, Benjamin Montesinos (INTA-CSIC), Brenda Matthews (NRC Canada), Agnes Kospal (Leiden), Mark Wyatt, Grant Kennedy (Cambridge), Debra Fischer (Yale), David Ardila (NHSC), George Rieke, Kate Su (Arizona) Niagara Escarpment An example of erosional processes: water, ice (glaciers) Geof, Karl, & Chas representing The DUNES Team Niagara Escarpment An example of erosional processes: water, ice (glaciers), planet? Geof, Karl, & Chas representing The DUNES Team Goals Imaging/modeling of individual systems - Determine the location of dust relative to the planets - Image planet-induced disk structure Statistical properties of the overallGeo fsample, Karl, & Chas - Look for a correlation between planets andrepresenting debris The DUNES Team - Correlate debris with specific types of planets Summary We find a significant correlation between radial-velocity planets and Herschel debris disks Why might planets and disks be correlated? • Initial disk conditions (Wyatt+ 2007) • Distant interaction (Moro-Martin+ 2007) • Close interaction (Wyatt 1999) • Planetesimal scattering to outer disk (Lin) Geof, Karl, & Chas predict correlation with high-mass representingplanets The DUNES Team • Current systemwide instability (Booth+ 2009) • Earlier systemwide instability (Raymond+ 2011) predicts correlation with terrestrial planets Planet-induced Disk Structure Fomalhaut b – beta Pic b – eccentricity/semi-major axis planet mass/semi-major axis predicted by Stapelfeldt (2004) prediction by Mouillet (1997) based on Spitzer ofset based on inner disk warp HR 8799 b,c,d,e – two-belt structure suggestive of intermediate planets (cf. the Solar System) Overall – Clear examples of planet-disk interaction, but not planet-disk correlation HD 202628: a Fomalhaut-like KLIF HST/STIS image HD 202628 is the faintest debris disk observed in scattered light (Krist et al 2012) - ~2-Gyr-old, G2V star at 24 pc - asymmetric, ofset ring - sharp inner disk edge - e=0.18, a=158 AU - detected out to 254 AU Deprojected 10" (244 AU) (KLIF = Kuiper-belt with Lovely Imaged Features) HD 202628: a Fomalhaut-like KLIF HST/STIS image HD 202628 is the faintest debris disk observed in scattered light (Krist et al 2012) - ~2-Gyr-old, G2V star at 24 pc - asymmetric, ofset ring - sharp inner disk edge - e=0.18, a=158 AU - detected out to 254 AU Deprojected 10" (244 AU) (KLIF = Kuiper-belt with Lovely Imaged Features) DUNES DUst around NEarby Stars How much dust do stars like the Sun have? Where is it located? What produces the dust? Is the Solar System normal? PI: CarlosGeo Eiroaf, Karl,(U.A.Madrid) & Chas Open Time Key Program representing The DUNES Team 239 main-sequence FGK stars within 25 pc (133 primary targets + 106 shared with DEBRIS) Primarily PACS 100/160um imaging some PACS 70um for known disks and some SPIRE 250/350/500um follow-up S/N=7 planned sensitivity at 100 um some DUNES results q1 Eri (Liseau+ 2010; Augereau+) - ~100 AU radius - R-V planet at 2 AU - HST/ACS (Stapelfeldt+) HD 207129 (Marshall+ 2011; Loehne+ 2011) - very large; ~150 AU - ring-like - HST/ACS (Krist+ 2010) zeta2 Ret (Eiroa+ 2010) - strong asymmetry/ofset - consistent with e=0.3 - may harbor alien life Search for Kuiper-belts Around Radial-velocity Planet Stars SKARPS sample definition: - at least one radial-velocity-detected exoplanet - F, G, or K spectral type; luminosity class IV/V - brighter than Ks = 6 mag - not in the galactic plane (|b| > 3°) 99 stars meet these criteria 32 observed by key programs (Marshall et al 2012) 67 new targets (all but 2 now observed) New debris disks around planet-bearing stars IR excess is detected around 29 out of 97 planet-bearing stars (30+-6%, cf. 45 out of 203 = 22+-3% in control sample). 17 were known pre-Herschel; 12 are new debris disk detections Herschel strengths for detecting solar-type debris disks: 1) better sensitivity 2) longer wavelength observations closer to the emission peak 3) multiple wavelength coverage helps to confirm the detection and to determine the dust temperature HD 50499 HD 72659 Tdust=32 K Tdust=44 K green=Spitzer red=Herschel Resolved Debris Disks Most of the disks are resolved by Herschel, providing good constraints on the location and properties of the emitting dust. HD 1461 HD 128311 100um 70um (FWHM ~6”) (FWHM ~4”) disk radius ~4” ~50 AU = 100 AU Moro-Martin et al, in prep GJ 581 HD 50554 70um 70um ~30 to 60 AU disk radius ~4” = 120 AU Lestrade et al, submitted Herschel images of HD 38858 model model data (convolved) (raw) residuals 10" 70um mean SB:0.469 mJy/sq" 10" Kennedy et al, 70μm in prep 100AU Obs Model 100AU HiResModel Residuals ±2-3 contours 10" 160um mean SB:0.324 mJy/sq" 10" 160μm 100AU Obs Model 100AU HiResModel Residuals ±2-3 contours An example of a planet-bearing star well resolved by Herschel with no evidence of any disk asymmetry. (not detected by Hubble) DistribuPons of Disk Brightness à A correlation between disk brightness (relative to the star) and the presence of an RV planet (>99% confidence) Are debris disks associated with a parPcular type of planet? Wyatt et al 2012 (using only Spitzer data) Among the 60 nearest G stars, 11 have known planets. Above Saturn mass, no disks (0/5) Below Saturn mass, lots of disks (4/6) Are debris disks associated with a parPcular type of planet? In the full Herschel data set, no clear trends Correlaon with Metallicity à High metallicity stars have somewhat brighter disks (only 80% confidence) Summary Based on a Herschel survey of planet-bearing stars, we find: >10 new planet-bearing stars with debris disks >10 newly resolved planet-disk systems no evidence of planet-induced asymmetry a correlation between inner gas-giant planets and cold outer-disk debris no correlation with planet mass/location weak trend with metallicity Possible (simplest) interpretation: Protoplanetary disks vary (mass, lifetime, etc) Some are better at making large bodies throughout .
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