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Evolution of Debris Disks

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Evolution of Debris Disks Placing Our Solar System in Context Michael R. Meyer Steward Observatory, The University of Arizona D. Backman (NASA-Ames, D.P.I.) , S.V.W. Beckwith (STScI), J. Bouwman (MPIA), T. Brooke (Caltech), J.M. Carpenter (Caltech), M. Cohen (UC-Berkeley), U. Gorti (NASA-Ames), T. Henning (MPIA), L. Hillenbrand (Caltech, D.P.I.), D. Hines (SSI), D. Hollenbach (NASA- Ames), J. Lunine (LPL), J.S. Kim (Steward), R. Malhotra (LPL), E. Mamajek (CfA), A. Moro-Martin (Princeton ), P. Morris (SSC), J. Najita (NOAO), D. Padgett (SSC), I. Pascucci (Steward), J. Rodmann (MPIA), W. Schlingman (Steward), M. Silverstone (Steward), D. Soderblom (STScI), J.R. Stauffer (SSC), B. Stobie (Steward), S. Strom (NOAO), D. Watson (Rochester), S. Weidenschilling (PSI), S. Wolf (MPIA), and E. Young (Steward). From Active Accretion to Planetary Debris Disks... Images courtesy of K. Stapelfeldt, P. Kalas, and NASA. Planetary debris disk ~ 100 Myr old Solar system debris disk 4.65 Gyr old! 12 Gas-rich disk ~ 1 Myr old Diversity in Primordial Disk Masses and Lifetimes Haisch etal. 2001; see also Hillenbrand (2002). < t > ~ 3 Myr Terrestrial Planets? Frequency CAI Formation? Chrondrules? Inner Disk Lifetime Different Wavelengths Trace Different Radii! NIR MID FIR sub-mm 0.1 1.0 10.0 100 AU Star with magnetospheric accretion columns Accretion disk Infalling Disk driven envelope bipolar outflow The Transition between Thick & Thin: •Primordial Disks: » Opacity dominated by primordial grains. Approximately 3-300 Mearth available in solids. •Debris Disks: » Opacity dominated by grains produced through collisions of planetesimals. Could be true in gas-rich disk, but how would one know? •How can you tell the difference? » Absence of gas (Gas/Dust < 0.1) argues for short dust lifetimes (blow-out/P-R drag). The transition time from MIR thick to thin is << 1 Myr years. Silverstone et al. (ApJ, 2006). See also Wolk and Walter, 1996; Kenyon and Hartmann, 1995; Prato and Simon, 1995; Skrutskie et al. 1990. Out of a sample of > 70 stars 3-30 Myr old, 5 optically-thick disks, and no optically-thin disks. MIR MIR Excess Emission: Probing Remnant Disks 0.3-1 AU over time... Upper limits correspond to optically-thin disks with very Chrondrules? CAI Formation? Terrestrial Planets? small dust masses. Mamajek et al. 2004, ApJ. MIR MIR Excess Emission: Probing Remnant Disks 0.3-1 AU over time... Approx. x1000 current solar system levels. s? e al Planets? Chrondrul CAI Formation? Terrestri Mamajek et al. 2004, ApJ. MIR Excess Fraction (0.3-1.0 AU) CAI Formation? vs. Cluster Age Chrondrules? Dust in terrestrial planet zone dissipates soon after accretion stops! Terrestrial Planets? Mamajek et al 2004, ApJ. Weinberger et al. (2004). Silverstone et al. (2006). Spitzer IRS Reveals ``Needle'' in FEPS MIR Haystack Warm debris belt 4-6 AU around 30 Myr old sun-like star! Hines et al. (2006) Asteroid Belt Analogues: Rare Example MIR of Warm Terrestrial Debris Around HD 12039 NASA/JPL-Caltech; T. Pyl, SSC. See Hines et al. (ApJ, 2006) MIR A Stars vs. G Stars: What Should We Expect? •Detectability: » Flux-limited excess detection... – F(v) ~ Σd x sqrt(L*) => A stars less dust » Relative to Stellar Photosphere (colors)... – F(v) ~ Σd / sqrt(L*) => A stars more dust •Planetesimal Formation Timescales: »tp ~ ρp x Rp / [ σd x Ωd] 3 – σd ~ M*/a and Ωd~ sqrt(M*/a ) – following Goldreich et al. (2004) A Stars vs. G Stars: What Should We Expect? A Stars vs. G Stars: What Should We Expect? Spitzer Results for Debris Disks MIR Surrounding Intermediate Mass Stars Rieke et al. (2005) Evolution of A Star Debris: Theory MIR Kenyon and Bromley (2004; 2005; 2006) Emergence of A Star Debris: MIR Theory Meets Observations in Orion? Hernandez et al. (2006) G stars MIR Detection corresponds to 5 x 10-5 Mearth in dust. Meyer et al. (5:00 am Thursday morning) Evolution of 24 Micron Debris: MIPS Team MIR View Gorlova et al. (2006); Siegler et al.; Rieke et al. (2005); Bryden et al. (2006) Evolution of 24 Micron Debris: FEPS Team MIR View FEPS Meyer et al. (in preparation). Evolution of 24 Micron Debris: Additional Perspectives MIR FEPS Hernandez et al. (2006); Padgett et al.; Bouwman et al.; Carpenter et al. (2006) Solar System Timescales for Comparison MIR CAIs Vesta/Mars LHB Chondrules Earth-Moon FEPS Hernandez et al. (2006); Padgett et al.; Bouwman et al.; Carpenter et al. (2006) Solar System Timescales for Comparison MIR CAIs Vesta/Mars LHB Chondrules Earth-Moon Note to Self: FEPS a) Fractions observed are lower limits. b) 24 micron emission comes from range of temp/radii [0.4-150 AU]. c) Detailed comparison to Kenyon and Bromley models needed! Hernandez et al. (2006); Padgett et al.; Bouwman et al.; Carpenter et al. (2006) Effect of Gas Giant Planets? Constraints from the Asteroid Belt... MIR Bottke et al. (2005) The Late-Heavy Bombardment and the Dynamical History of the Solar System FIR An old Fairy Tale: New Fairy Tales... Thommes et al. (2002) Morbidelli et al.; Gomes et al.; and Tsiganis et al. (2005) Strom et al. (2005); and Bottke et al. (2005) Spectroscopic Observations of Transient MIR Dust Debris Surrounding Sun-like Stars Beichman et al. (ApJ, 2005); See also Song et al. (Nature, 2005) FIR Outer Disks (1-10 AU) vs. Time FIR Classical Evolution or Punctuated Equilibrium? Habing et al. (1999) Meyer et al. (2000) Habing et al. (2001) Spangler et al. (2001) Greaves et al. (2003) Sub-mm Photometry: Dust Mass over Time? ? CAI Formation? Chrondrules? SMM Terrestrial Planets? Late Heavy Bombardment Wyatt et al. (2003); Carpenter et al. (2005) HD 107146: Debris Disk SMM Surrounding 100-300 Myr G star Williams et al. (2004) ApJL. Ardila et al. (2005). Debris Disks vs. Metallicity: More “diverse” than RV planet systems Greaves, Fischer, and Wyatt (2006). FIR 30+- 10 Myr 45 to ??? AU -7 Surveys for ~1x10 Msun Cold Outer Debris Disks 700+- 300 Myr 20 to <100 AU -8 ~6.9x10 Msun Meyer et al. (2004) Kim et al. (2005) Hillenbrand et al. (2006) Surveys for FIR Cold Outer Debris Disks a) 10-20 % overall; indep. of age. b) scatter in dust mass at all ages but dropping. c) evidence for extended debris? Kim et al. (this meeting) Hillenbrand et al. (2006) Do Stars with Planets Also Have Kuiper FIR Disks? Beichman et al. (2005) The connection between dust emission and and emission dust between connection The presence/absence of planets is not clear. clear. not is planets of presence/absence Dust Production P l a n e t s Time N o P l an et s Effect of Gas Giant Planets? Long-term Evolution of Planetesimal Belts... MIR Meyer et al. (2006); Backman et al. (in preparation). Debris Disks vs. Binarity: Debris not inhibited by companions. MIR Stansberry et al. (this meeting); Trilling et al. submitted. Is Our Solar System Common or Rare? CAIs? Chond? TPF? t - 1 FIR/ SMM LHB? t - 2 Is Our Solar System Common or Rare? CAIs? Κ Chond? TPF? t FIR/ -1 SMM LHB? Κ t - 2 1000-3000 300-1000 100-300 Lifetime (Myr) 30-100 10-30 3-10 FEPS FEPS < 0.1 0.3-1.0 1-10 30-100 30-100 1-10 0.3-1.0 0.1 < Preliminary Preliminary 8 8 Results: Debris Disk Lifetimes Disk Debris Results: Radius (AU) Radius FEPS Preliminary Results: Does Gas Persist? < 0.1 0.3-1.0 1-10 30-100 Radius (AU) ) r y 3-10 Gas? M ( e 10-30 m i t 8 e f i 30-100 L 8 100-300 300-1000 1000-3000 http://feps.as.arizona.edu Spitzer Initial Results: Executive Summary ● Terrestrial temperature dust gone < 10 Myr. ● Gas disk lifetimes still uncertain but probably < 10 Myr. ● 24 Micron Debris from 1-20 AU preferentially 10-300 Myr. ● 70 Micron Kuiper Disk analogues Are common: ~ 10-20 % over all ages. Meyer et al. Protostars and Planets V (Arizona Space Science Series, in press) Implications for Formation and Evolution of Planetary Systems? ● Inner disk debris around other stars observed during epoch of solar system terrestrial planet formation but is difficult to distinguish from end of primordial disk phase. ● Short-lived events observed in some systems consistent with stochastic evolution of dynamical systems. ● No strong evidence for differences in debris disk evolution with stellar mass. ● No strong evidence for difference in debris disk evolution with metallicity or presence/absence of RV giant planets. ● No strong evidence that debris disks are suppressed in binary systems (possibly enhanced?). ● Consistent with many stars forming swarms of planetesimals. What can we learn from those that don't? Implications for Formation and Evolution of Planetary Systems? ● Inner disk debris around other stars observed during epoch of solar system terrestrial planet formation but is difficult to distinguish from end of primordial disk phase. ● Short-lived events observed in some systems consistent with stochastic evolution of dynamical systems. ● No strong evidence for differences in debris disk evolution with stellar mass. ● No strong evidence for difference in debris disk evolution with metallicity or presence/absence of RV giant planets. ● No strong evidence that debris disks are suppressed in binary systems (possibly enhanced?). ● Consistent with many stars forming swarms of planetesimals. What can we learn from those that don't? Implications for Formation and Evolution of Planetary Systems? ● Inner disk debris around other stars observed during epoch of solar system terrestrial planet formation but is difficult to distinguish from end of primordial disk phase. ● Short-lived events observed in some systems consistent with stochastic evolution of dynamical systems. ● No strong evidence for differences in debris disk evolution with stellar mass.
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