1 / 54

Protostellar Disks: Birth, Life and Death

National Aeronautics and Space Administration. Protostellar Disks: Birth, Life and Death. Neal Turner Jet Propulsion Laboratory, California Institute of Technology. Death of Protostellar Disks. Origins of the gas giant planets Dispersal of remnant material

mirit
Download Presentation

Protostellar Disks: Birth, Life and Death

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. National Aeronautics and Space Administration Protostellar Disks: Birth, Life and Death Neal Turner Jet Propulsion Laboratory, California Institute of Technology

  2. Death of Protostellar Disks Origins of the gas giant planets Dispersal of remnant material Origins of the terrestrial planets Debris disks Key issues for the future National Aeronautics and Space Administration

  3. National Aeronautics and Space Administration

  4. Fischer & Valenti 2005 National Aeronautics and Space Administration

  5. National Aeronautics and Space Administration

  6. Hubickyj et al. 2005 Core Accretion total solid core gas envelope National Aeronautics and Space Administration

  7. Gravitational instability with cooling time < orbital period. Lufkin et al. 2004 National Aeronautics and Space Administration

  8. Marcy et al. 2005 National Aeronautics and Space Administration

  9. Tidal Torques in the Disk • This leads to: • Gap Formation • Orbital Migration National Aeronautics and Space Administration

  10. Type I Migration: Rocky Cores Nelson et al. 2000 National Aeronautics and Space Administration

  11. Kley & Crida 2008 National Aeronautics and Space Administration

  12. Kley & Crida 2008 National Aeronautics and Space Administration

  13. Type II Migration: Giant Planets Bryden & Lin 1996 National Aeronautics and Space Administration

  14. Gap-Opening Criterion Equilibrium gap width balances gap-opening tidal torques with gap-closing pressure + viscous forces. Planetary tides overwhelm the pressure if the Hill sphere is bigger than the disk thickness: The tides overwhelm the disk viscosity if: National Aeronautics and Space Administration

  15. Dispersal of Remnant Disk Material National Aeronautics and Space Administration

  16. Haisch et al. 2006 National Aeronautics and Space Administration

  17. Jayawardhana et al. 2006 National Aeronautics and Space Administration

  18. Andrews & Williams 2005 National Aeronautics and Space Administration

  19. National Aeronautics and Space Administration

  20. Richling & Yorke 2000 National Aeronautics and Space Administration

  21. Photoevaporative Clearing Gas ionized by UV photons from the star or nearby stars heats to a temperature T ~104 K. Outside the gravitational radius, the sound speed exceeds escape speed and the gas flows almost radially away from the star. Outside a smaller critical radius, the vertical gas pressure gradient accelerates flows to escape. Liffman 2003 National Aeronautics and Space Administration

  22. Alexander et al. 2006 National Aeronautics and Space Administration

  23. Varnière et al. 2006 National Aeronauticsand Space Administration

  24. Terrestrial Planet Formation National Aeronautics and Space Administration

  25. Starting Condition is a Gas-Poor Planetesimal Disk Sizes ~ 1km. Weak gravitational interactions stir relative motions up to escape speed ~ 1 m/s. Collisions and mergers produce steady growth. National Aeronautics and Space Administration

  26. Dynamical Friction Equipartitions energy between big and small bodies v Drag National Aeronautics and Space Administration

  27. Gravitational Focusing Cross-section for collisions is enhanced by the gravitational pull of the body. b v National Aeronautics and Space Administration

  28. Gravitational Focusing Cross-section for collisions is enhanced by the gravitational pull of the body. National Aeronautics and Space Administration

  29. Runaway growth ends when… • The protoplanets stir up the remaining planetesimals, or • Most of the mass is in protoplanets, so dynamical friction is ineffective. • In either case, gravitational focusing grows weak. National Aeronautics and Space Administration

  30. Oligarchs Grow Model Solar System Chaos Nagasawa et al. 2007 National Aeronautics and Space Administration

  31. Canup & Asphaug 2001 National Aeronautics and Space Administration

  32. National Aeronauticsand Space Administration

  33. Debris Disks National Aeronautics and Space Administration

  34. Dust in the Solar System • Interplanetary dust particles are released by asteroid collisions & comet passages. • Particle concentration in the ecliptic plane causes zodiacal light. • Median size is 30m, but a wide range is seen. • Even though luminosity is just 10-7 of Solar, the zodiacal light is the most luminous component of our planetary system. National Aeronautics and Space Administration

  35. Collisional Families in the Asteroid Belt Nesvorny et al. 2002 National Aeronautics and Space Administration

  36. The Brightest Debris Disks: Fomalhaut Confined ring with radius 133-158 AU Offset center – eccentric ring forcing Dynamical modeling suggests planet; not yet confirmed National Aeronautics and Space Administration

  37. Augereau et al. 2001 The Edge-on Warped Disk of b Pictoris National Aeronautics and Space Administration

  38. Distribution of Disk Luminosities Trilling et al. 2008 Based on 70 μm data, ~12% of old F5-K5 stars have disks that intercept >10-5 of the stellar flux The grains are short-lived. Hence disruptive collisions releasing 100x more dust than the present Solar system are common! National Aeronautics and Space Administration

  39. Brighter disks are more common for RV planet hosts Bryden et al., submitted National Aeronautics and Space Administration

  40. Timescale for Loss of Debris The fraction of Sun-like stars found with warm dust declines with age over ~100 Myr From G. Bryden National Aeronautics and Space Administration

  41. Debris Disks vs. Metallicity No correlation! (very different from strong correlation of gas giant planets with metallicity) From G. Bryden National Aeronautics and Space Administration

  42. Brighter Kuiper Belts 1 From G. Bryden National Aeronautics and Space Administration

  43. Brighter Kuiper Belts 2 1984: Beta Pic 1999: HR4796A, HD141569 2005: 4 more 2006: 3 more 2007: 3 more 13 total with HST + 4 more submm + 4 others IR (see http://circumstellardisks.org) From G. Bryden National Aeronautics and Space Administration

  44. Key Questions for the Future National Aeronautics and Space Administration

  45. 1. What determines cloud core masses? Alves et al. 2007 National Aeronautics and Space Administration

  46. National Aeronautics and Space Administration

  47. 2. How is the angular momentum removed from disks? Mejia et al. 2005 National Aeronautics and Space Administration

  48. Model H2D+ 372.4 GHz Maps 300 y-offset / AU -300 -300 300 x-offset / AU Intensity units 10-6 erg cm-2 s-1 sr-1 Asensio Ramos et al. 2007 National Aeronautics and Space Administration

  49. 3. How do planetesimals form? Grain v=vK Cold, Less Dense Hot, Dense National Aeronautics and Space Administration

  50. National Aeronautics and Space Administration

More Related