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Formation and Evolution of Planetary Systems: The Makings of an Epicurean Feast

Michael R. Meyer Steward Observatory, The University of Arizona Steward/NOAO Joint Colloquium February 12, 2009. Formation and Evolution of Planetary Systems: The Makings of an Epicurean Feast. Different Flavors of Planet Formation.

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Formation and Evolution of Planetary Systems: The Makings of an Epicurean Feast

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  1. Michael R. Meyer Steward Observatory, The University of Arizona Steward/NOAO Joint Colloquium February 12, 2009 Formation and Evolution of Planetary Systems: The Makings of an Epicurean Feast

  2. Different Flavors of Planet Formation

  3. Are planetary systems like our own are common or rare among sun-like stars in the Milky Way galaxy? Q: What are the initial conditions of planet formation?Q: What is the time available to form gas giant planets?Q: What is the history of planetesimal collisions vs. radius? Q: How do the above vary with stellar properties?Because the answers are subtle, need large samples over a wide range of ages.

  4. From Active Accretion to Planetary Debris Disks... Planetary debris disk ~ 100 Myr old Solar system debris disk 4.56 Gyr old! 12 Gas-rich disk ~ 1 Myr old Images courtesy of M. McCaughrean, C.R. O`Dell, NASA, and P. Kalas. For recent review see Meyer et al. (2007) Protostars & Planets V

  5. Blackbody Disk with Dynamically Cleared Gap

  6. Star+ Dust Star+ Dust+ Disk H H Color_2 H Star+ Disk H Star Color_1 NICMOS/HST Mosaic F810W/F110W/F150W of NGC 2024 (Liu, Meyer, Cotera, and Young 2003, AJ)

  7. Inner (< 0.1 AU) Accretion Disk Evolution 0.1-10 Myr Does the observed range in initial disk mass (e.g. Andrews & Williams, 2005) explain the observed range in disk lifetimes? Haisch et al. 2001; Hillenbrand et al. (2002); Muzerolle et al. (2003). Terrestrial Planets? CAI Formation? Chrondrules?

  8. Inner (< 0.1 AU) Accretion Disk Evolution 0.1-10 Myr Haisch et al. 2001; Hillenbrand et al. (2002); Muzerolle et al. (2003). Terrestrial Planets? < t > ~ 3 Myr Frequency CAI Formation? Chrondrules? Inner Disk Lifetime

  9. Different Wavelengths Trace Different Radii! Star with magnetospheric accretion columns Accretion disk Infalling envelope Disk driven bipolar outflow NIR MID FIR sub-mm 0.1 1.0 10.0 100 AU

  10. Confounding Variables:T Tauri Disk Evolution and Errors in Age Transition Disks: Espaillat et al. (2007); Brown et al. (2007) Few disk parameters correlate: Bouwman et al. (2008) Pascucci et al. (2008) Cortes et al. (2008) Watson et al. (2007)

  11. Gail (2002); Cody & Sasselov (2005); Garaud & Lin (2007); Bond et al. (in prep) Image courtesy N. Gehrels (PSU) How does chemistry affect planet formation?

  12. Pascucci et al. (2007); Esplainat et al. (2007); Herzeg et al. (2007) FUV and (or?) X-rays in action…

  13. Pascucci et al. (in press); cf. Carr & Najita (2008) Gas disk chemistry may vary with stellar mass…

  14. Primordial Gas disk lifetimes appear to be < 10 Myr. No massive gas disks detected around 35 stars with ages 3-100 Myr. Less than 0.1 Mjup remains to form planets. Hollenbach et al. 2005; Pascucci et al. 2006/7; Lahuis et al. 2007 Debris Gas? Chen et al. 2007; Roberge et al. 2006; Dent et al. 2005

  15. Rapid Transition time thick to (very) thin inside 1 AU 74 stars 3-30 Myr old: => 5 gas-rich disks. => no optically-thin hot dust (< 1 AU). Silverstone et al. (2006); Cieza et al. (2007); and references therein.

  16. Planets as a Function of Stellar Mass: What Should We Expect? Planetesimal Formation Timescales: • tp ~ p x Rp / [ d x d] • d ~ M*/a and d~ sqrt(M*/a3) • following Goldreich et al. (2004); Kenyon & Bromley (2006). • Normalize: @ 3 Myr - [3 Mearth, 5 AU, 1 Msun] • tp ~ [p x Rp x a5/2]/ [M*3/2]. • Gives Jupiter mass gas giant planet. • Massive planets farther out surrounding stars of higher mass. • Consistent with observations to date (Johnson et al. 2007). • Yet disks last longer around stars of lower mass! [Lada et al. (2006); Carpenter et al. (2006).]

  17. Evolution of Disks Around Sun-like Stars: Tracing Planet Formation? (Field & Cluster) CAIs Vesta/Mars LHB Chondrules Earth-Moon 0.0 0.1 0.2 0.3 0.4 6.0 7.0 8.0 9.0 Meyer et al. (2008); Kenyon/Bromley (2006); Siegler et al. (2007); Currie et al. ‘07

  18. Evolution of Disks Around Sun-like Stars: Tracing Planet Formation? (Field & Cluster) CAIs Vesta/Mars LHB Chondrules Earth-Moon 0.0 0.1 0.2 0.3 0.4 6.0 7.0 8.0 9.0 Meyer et al. (2008); Kenyon/Bromley (2006); Siegler et al. (2007); Currie et al. ‘07

  19. Evolution of Disks Around Sun-like Stars: Tracing Planet Formation? (Field & Cluster) CAIs Vesta/Mars LHB Chondrules Earth-Moon 0.0 0.1 0.2 0.3 0.4 6.0 7.0 8.0 9.0 Meyer et al. (2008); Kenyon/Bromley (2006); Siegler et al. (2007); Currie et al. ‘07

  20. Observational Constraints on Planet Formation: Detecting Hot Protoplanet Collision Afterglows? Stephenson (1983); Stern (1994); Zahnle et al. (2007)

  21. 2M1207B: A Hot Protoplanet Collision Afterglow? (Chauvin et al. 2004; Schneider et al. 2005; Mohanty et al. 2007)

  22. Flux observed = Area x T4With log(L/Lo) = -4.54 and Teff = 1600 K, 2M1207B is 4-7 times fainter than expected for age.Hypothesis: 2M1207B is faint, because it is small.R ~ 8 Rearth corresponds to << 1 Mjup Mamajek & Meyer (2007)

  23. Miller-Ricci et al. (submitted)

  24. The connection between planetesimal belts and presence/absence of giant planets is not clear. Planets Dust Production No Planets Time

  25. Direct Detection of Gas Giant Planets No massive planets at large radii around debris disk targets with large inner gap Apai et al. (2008)

  26. No link between debris and RV planets found!Could debris disks be more common than Gas Giants? Moro-Martin et al. (2007a; 2007b) and Bryden et al. (2006) See Beichman et al. (2005); Lovis et al. (2006); Alibert et al. (2006) regarding HD 69830.

  27. Spitzer/FEPS (Meyer et al. 2006) The Last Word: Carpenter et al. (2008) Evolution in Disk Luminosity: A stars: Su et al. (2006) G stars: Bryden et al. (2006) M stars: Gautier et al. (2007) Distribution of Inner Hole Sizes

  28. A Picture is Worth 1024 x 1024 Points on an SED… Spitzer @ MIPS-24 JWST-MIRI

  29. Sub-mm Observations of Debris Disks: Carpenter et al. (2005); Greaves et al. (2006; 2008); Liu et al. (2004)

  30. Evolutionary Diversity: What role might multiplicity play? Complex Story T Tauri Binaries vs. SeparationDebris Disks not inhibited Simon & Prato (1995); Jensen et al. (1994) by companions! McCabe et al. (2006); White & Ghez (2001) Trilling et al. (2007) Patience et al. (2008); Pascucci et al. (2008) Wyatt et al. (2003)

  31. Are planetary systems like our own are common or rare among sun-like stars in the Milky Way galaxy? Primordial Disk Evolution:- disks around lower mass stars are less massive and live longer than their more massive counterparts.- large dispersion in evolutionary times could indicate dispersion in initial conditions.- evolution appears to proceed from inside-out as expected.

  32. Are planetary systems like our own are common or rare among sun-like stars in the Milky Way galaxy? Change you can believe in!- transition time from primordial to debris is << 1 Myr.- planetesimal belts evolve quickly out to 3-30 AU.- any evidence for warm dust gone by 300 Myr.- some evidence that warm debris more common in clusters?

  33. Debris Disk Evolution:- currently detectable systems are collision-dominated.- more common around stars of higher mass. - evolutionary paths are diverse.- consistent with our solar system being common.- connection to planetary systems unclear.Are systems without debris those with dynamically full planetary systems, or those without any planets?

  34. Benefits of Direct Detection: • Enable estimate of internal energy source of planet: • Assess energy available for life. • Viability of planet tectonics? [Valencia et al. 2007]. • Enable study of atmospheric composition: • Assess possible surface chemistry. • Non-equilibrium chemistry [Kaltenegger et al. 2007]? • Unique tool to understand planet formation! • ‘Merger tree’ determines heating (volume) to cooling (surface area).

  35. Studying Disks and Planets in 2013? Meyer et al. (2007) “In the Spirit of Bernard Lyot” NIRCam Instrument (M. Rieke, PI) FGS/TFI Instrument (R. Doyon, PI) MIRI Instrument (Rieke & Wright) Diffraction Suppression Techniques: Krist et al. (2007) Sivaramakrishnan et al. 2008

  36. Direct Detection: Solving The Problem To find other Earths, the problem is detail, not light gathering.

  37. The Next Big Step: Extremely Large Telescopes

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