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Pawel Artymowicz, University of Toronto at Scarborough

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  1. PSCD01 - 11 Oct. 2005 UTSC Exoplanetary science: origin and evolution of planetary systems Pawel Artymowicz, University of Toronto at Scarborough

  2. Understanding of extrasolar and solar planetary systems through theory of their formation • Introdroducing extrasolar systems • Protoplanetary disks • Disk-planet interaction: resonances and torques, numerical calculations, mass buildup, migration of planets • Dusty disks in young planetary systems • Origin of structure in dusty disks

  3. Already the Ancient... …had a good theory of star and planet formation

  4. Some of the earliest recorded physics was very far-sighted & essentially correct! Predicted: evolution (formation/decay), role of disks, and diversity of “worlds”=planets. Atomists (Ionian materialists) devoted 50% of their philosophy to cosmos, not microcosmos

  5. HOW ANCIENT GREEK ATOMISTS deduced ("invented") other worlds 480C.) Leucippus C.) Democritus bibliography: 60 vol, none survived THEN: = NOW: Worlds () Planetary systems (terra firma + atmosphere + moons + sun + stars) matter: - made of the same types cosmic (solar)abundance atoms and void everywhere - evolving yes - large variety yes - include Earth-like worlds ? NASA's goal

  6. From: Diogenes Laertius,  (3rd cn. A.D.), IX.31 “The worlds come into being as follows: many bodies of all sorts and shapes move from the infinite into a great void; theycome togetherthere and produce asingle whirl, in which,collidingwith one another andrevolvingin all manner of ways, they begin to separate like to like.” Leucippus (Solar nebula of Kant & Laplace A.D. 1755-1776? Accretion disk?) “There are innumerable worlds which differ in size. In some worlds there is no Sun and Moon, in others they are larger than in our world, and in others more numerous. (...) in some parts they are arising, in others failing. They are destroyed by collision with one another. There are some worlds devoid of living creatures or plants or any moisture.” Democritus (Planets predicted: around pulsars, binary stars, close to stars?) There are infinite worlds both like and unlike this world of ours.For the atoms being infinite in number (...) there nowhere exists an obstacle to the infinite number od worlds. Epicurus (341-270 B.C.)

  7. (...) it follows that there cannot be more worlds than one. Aristotle [On the Heavens] Aristotle's work rediscovered and enthusiastically accepted during the12th century Renaissance at the new universities (Paris, Oxford) e.g., Roger Bacon (1214-1292) cites the impossibility of vacuum between the hypothetical multiple worlds. Thomas Aquinas (1225-1274) also accepts Aristotle's arguments about impossibility of other worlds, despite a growing controversy within Church. Plato and Aristotle

  8. Obviously, a very ancient and worthy quest… …as well as controversial

  9. OTHER WORLDS: the pendulum starts swinging Franciscans: God can create other worlds. Idea of Earth's uniqueness censored under the threat of excommunication : In 1277 bishop of Paris, Etienne Tempier, officially condemns 219 passages from Aristotle taught at universities, among others that "the First Cause cannot make many worlds". Manysupporters of other worlds, e.g., William of Ockham (ca.1280-1347). Mikolaj Kopernik's heliocentric system (1543) seen as supporting other worlds. Giordano Bruno:infinite number of inhabited terrestrial planets. Burned at stake 1600 by Holy Roman Inquisition (though not predominantly for that!). William of Vorilong (ca. 1450) thought that it is"not fitting"for Christ to go to another world to die again. And there is no mention of other worlds in Scriptures. Johannes Kepler (1571-1630)did not believethat stars are distant suns or that they may have planets. And so on, until the end of 20th century came...

  10. Kant-Laplace nebula ~ primitive solar nebula ~ accretion disk ~ protoplanetary disk ~ T Tauri disk R. Descartes (1595-1650) - vortices of matter -> planets I. Kant (1755) - nebular hypothesis (recently revived by: Cameron et al, Boss) P.S. de Laplace (1796) - version with rings

  11. Stars and Brown Dwarfs …form in stellar nurseries from/with protostellar disks

  12. How Do Stars Form?

  13. Oph Giant Molecular Cloud, 160 pc away contains numerous dark clouds

  14. GMCs contain: dark clouds, cores, Bok globules GMC mass / solar mass ~ 105 Oph V380 Ori + NGC1999

  15. Dark clouds L57 Barnard 68

  16. UKAFF (UK Astroph. Fluid Facility) Our tools… parallel supercomputers: dozens to thousands of fast PCs connected by a very fast network UTSC: SunGrid cluster, ~200 cpus

  17. ANTARES/FIREANT Stockholm Observatory 20 cpu (Athlons) mini-supercomputer (upgraded in 2004 with 18 Opteron 248 CPUs inside SunFire V20z workstations)

  18. Matthew Bate (2003), Bate and Benz (2003) SPH, 1.5M particles starting from turbulent gas cloud

  19. Simulations produce large numbers of Brown Dwarfs

  20. Brown Dwarfs in Ophiucus Numerous

  21. Trapezium cluster in Orion with many Brown Dwarfs HST/NICMOS F110W+F160W

  22. There are rater few suchstar-bound brown dwarfs (so-called brown dwarf desert) but… the desert isn’t barren: 5 M_jup planet around a 25 M_jup Brown Dwarf in 2MASS1207 ESO/VLT AO HST/NICMOS, 1.6um

  23. Primordial disks have many names: protostellar disks T Tau disks proplyds protoplanetary disks solar nebulae

  24. Protoplanetary disks = = protostellar disks = solar nebulae

  25. Young protoplanetary disks (proplyds) are rather bland in appearance No gaps or fine detail seen in the density, except for rather sharp edges <== photoevaporation Photoevaporation is like boiling off gas by striking the hydrogen atoms with UV photons, kicking electrons and ions, and raising local kT to conditions resembling HII regions. Photoevaporation only works in regions where gravitational binding energy is less than kT: outer parts of cloud complexes, far-away disk regions gravitational binding = grav.potential well’s depth = -GM(r)/r (for spherical systems)

  26. Percentage of optically thick “outer disks” (at ~3 AU) From: M. Mayers, S. Beckwith et al. Conclusion: Major fraction of dust cleared out to several AU in 3-10 Myr This is the timescale for giant planet formation 0.1 1 10 100 1000 Myr Age

  27. The evolutionary sequence The birth of planetary systems

  28. Formation of disks and planets up to T Tau phase

  29. Formation of disks and planets post- T Tau phase

  30. <1 Myr 5 Myr 20 Myr 200 Myr 4567 Myr

  31. Dusty disks around main-sequence stars 1. Transitional 2. Debris disks 3. Zodiacal light

  32. Infrared excess stars (Vega phenomenon)

  33. Source: P. Kalas

  34. At the age of 1-10 Myr the primordial solar nebulae = protoplanetary disks = T Tau accretion disks undergo a metamorphosis A silhouette disk in Orion star-forming nebula Beta Pictoris They lose almost all H and He and after a brief period as transitional disks, become low-gas high-dustiness Beta Pictoris systems (Vega systems).

  35. Prototype of Vega/beta-Pic systems

  36. B Pic b(?) sky? Beta Pictoris 11 micron image analysis converting observed flux to dust area (Lagage & Pantin 1994)

  37. Chemical basis for universality of exoplanets: cosmic composition (Z=0.02 = abundance of heavy elem.) cooling sequence: olivines, pyroxenes dominant, then H2O

  38. Hubble Space Telescope/ NICMOS infrared camera

  39. HD 141569A is a Herbig emission star >2 x solar mass, >10 x solar luminosity, Emission lines of H are double, because they come from a rotating inner gas disk. CO gas has also been found at r = 90 AU. Observations by Hubble Space Telescope (NICMOS near-IR camera). Age ~ 5 Myr transitional disk

  40. HD 14169A disk (HST observations), gap confirmed by the new observations

  41. HD 141569A: Spiral structure detected by (Clampin et al. 2003) Advanced Camera for Surveys onboard HubbleSpace Telescope • Gas-dust coupling? • Planetary perturbations? • Dust avalanches?

  42. Radial-velocity planets around normal stars