1 / 45

Formation of the solar system

Formation of the solar system. Origin of basic properties. Descartes, Kant, Laplace. Basic Objectives. 1. To find clues on the planet formation mechanisms & time scales To identify signatures of planet-bearing stars. Central Issues. How do planets form so prolifically?

tanika
Download Presentation

Formation of the solar system

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. Formation of the solar system

  2. Origin of basic properties

  3. Descartes, Kant, Laplace

  4. Basic Objectives • 1. To find clues on the planet formation mechanisms & time scales • To identify signatures of planet-bearing stars Central Issues • How do planets form so prolifically? • How do we characterize the essential properties of planets? • Is the solar system architecture a rule or an exception? Methodology & approach • Spectroscopic and photometric observations • Outer solar system exploration • Meteoritic analysis • Fractionation of heavy elements through dust evolution • Core accretion model of planet formation • Planetary orbital migration • Long term planetary dynamical evolution

  5. Astronomical disks

  6. Sites of star & disk formation

  7. Angular momentum Angular momentum = mass x speed x radius

  8. Contraction & spin up Angular momentum = speed x radius Shrinking radius => spin up

  9. HST images give size & S(r) O’Dell & Wen 1992, Ap.J., 387, 229. Section of the Orion Nebula 218-354 183-405 100 AU radius 206-446 114-426 2000 AU 400 AU McCaughrean & O’Dell 1996, AJ, 108, 1382.

  10. Comparison with the solar nebula

  11. Mass distribution in the solar nebula

  12. Solar Nebula Disks can build planets Limit Beckwith & Sargent 14 Taurus Ophiuchus 12 Andre & Montemerle 10 8 6 4 2 0 1 0.0001 0.001 0.01 0.1 Mdisk (M¤) assumes gas/dust = 100

  13. Economic analogy Conclusion: rental houses are mostly owned by the top 10%

  14. Observations: young stars • Continuum radiation: dust mass distribution (MMSN x 3) • Sizes and surface density distribution (100 AU, S~r-1) • Gas accretion rate (10-8 M yr-1) • Grain phases and size evolution (growth and sedimentation) • Coexistence of hydrogen gas and dust grains (gas depletion) • Disk frequency evolution time scale in clusters (10 Myr) • Debris disk structures (embedded companions?)

  15. Inner disks disappear ~ 10 Myr Hillenbrand & Meyer 2000, in preparation 1.0 r Oph CrA N2024 0.8 N1333 Mon R2 Trap Taurus 0.6 LHa101 N7128 L1641y Fraction of disks L1641b ONC 0.4 Lupus IC 348 N2264 Cha 0.2 TW Hyd Pleiades Hyades 0.0 a Per Ursa Major 10 100 1 Gyr 1 0.1 Age (Myr)

  16. Time scale determination from age distribution Conclusion: 1) college students are mostly young adults, 2) bachelor’s degree takes 4-5 years on average

  17. Condensation of dust & growth of planetesimals

  18. Disk heating Internal dissipation stellar irradiation

  19. Different phases of ice

  20. Condensation sequence

  21. Elemental abundance in meteorites Similar to the Sun

  22. Isotopic anomaly

  23. Elements and Isotopes

  24. Radiometric dating

  25. Nuclear chronology Half life

  26. Decay of radioactive isotopes

  27. Range of half life U 238: 4.47*109 yearsTh 234: 24.1 daysHe 4: StablePa 234: 6.7 hoursC 11: 20.3 minutesB 11: stableU 235m: 26 minutesU 235: 7.04*108yearsFm 256: 2.62 hoursXe 140: 13.6 secondsPd 112: 21 hoursPo 212: 299 nanosecondsSe 82: 1.3*1020 years Solar system: 4.6 Gyr old

  28. Chondritic meteorites • Limited size range, sm-cm, • Glass texture, flash heating, • Age difference with CAI’s, • Matrix glue & abundance, • Weak tensile strength. • Formation timescale 2-3 Myr

  29. Supernova precursor Injection of radioactive Al26

  30. Differentiation & fragmentation

  31. Solar system exploration: formation

  32. Coagulation of planetesimals

  33. Collisions: piles of loose fragmentation Weak sticking strength Shared orbits and repeated encounters Piles of loose gravel (coagulation vs collapse)

  34. Preferred cradles of gas giants: snow line Limited by: Isolation slow growth

  35. Impact growth & craters

  36. Magma ocean, differentiation

  37. time of terrestrial formation

  38. Planets on the move

  39. Iron fingers & double diffusive instability Heat transport bottleneck Many channels to bypass the heat barrier and shorten the growth time scale

  40. Gas accretion

  41. Gas giant gap formation & migration

  42. Multiple gas giants

  43. Gas giants’ environmental impact

  44. Disk clearing Stellar magnetosphere Photo-evaporation Stellar wind

  45. Scattering & Ejection Thommes

More Related