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Star & Planet Formation

Star & Planet Formation. Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics. Galaxy. Dimitar. Molecular Cloud Complex. Star Cluster. Star-Forming “Globule”. Circumstellar Disk. Number of Stars of each Mass. Extrasolar System. Stellar Mass.

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Star & Planet Formation

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  1. Star & Planet Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics

  2. Galaxy Dimitar Molecular Cloud Complex Star Cluster Star-Forming “Globule” Circumstellar Disk Number of Stars of each Mass Extrasolar System Stellar Mass Which Stars form Where, When, and How? ? ?

  3. Mass Matters

  4. Orion Constellation Movie

  5. Galaxy Molecular Cloud Complex Star Cluster Star-Forming “Globule” Circumstellar Disk Number of Stars of each Mass Extrasolar System Stellar Mass Which Stars form Where, When, and How? ? • Implications • -evolution of galaxy’s gas & stars with time • -variety/longevity of extrasolar systems

  6. Star-Forming Region in Perseus 60 light years Image by E.E. Barnard, c. 1907

  7. FLAMINGOS J,H,K Composite; Muench et al. 2003 IC348 Brightness & color measurements give information on the mass distribution (“IMF”) of stars, and the DISKS around those stars. 60 light years

  8. log (# stars) log (Stellar Mass) Luhman et al. 2003 How many stars of each mass form? “IMF” Initial Mass Function of Stars Number of Stars of each Mass Stellar Mass

  9. FLAMINGOS J,H,K Composite; Muench et al. 2003 How does the IMF vary with environmental conditions? IC 348: Luhman et al. 2003; Taurus: Briceño et al. 2002

  10. Key Questions How does the IMF vary with environment? How fast do clouds & stars form? What creates variety in “protoplanetary” disks?

  11. Science&Technology

  12. Simulations as Data Interpretation Data: Censes of Young Stars Radio spectral-line maps of gas motions Thermal-continuum maps of dust emission & photos of dust extinction Dynamic Range >104 Simulations: Including effects of gravity, magnetic fields, chemistry, heating & cooling, stars forming, & thermal pressure…but not all at once (yet) Dynamic Range <102 Simulated spectral-line map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan, Goodman &Juvela 2003

  13. [ ] T / 10 K b = [ ] 2 -3 [ ] n B m / 100 cm / 1 . 4 G H 2 Synthetic Star Forming Regions Strong Magnetic Field Weak Magnetic Field b=0.01 b=1 • Driven Turbulence; M K; no gravity • Colors: log density • Computational volume: 2563 • Dark blue lines: B-field • Red : isosurface of passive contaminant after saturation Stone, Gammie & Ostriker 1999

  14. Simulations Let Us Live Longer • MHD turbulence (another simulation) gives initial conditions • 50 Msun, ~1 lyr, navg=3 x 105 ptcls/cc • forms ~50 objects • T=10 K • SPH, no magnetic fields or heating and cooling • movie=1.4 free-fall times Bate, Bonnell & Bromm 2002; c.f. Ostriker, Stone & Gammie 2001

  15. Circumstellar Disks

  16. Galaxy Molecular Cloud Complex Star Cluster Star-Forming “Globule” Circumstellar Disk Number of Stars of each Mass Extrasolar System Stellar Mass Which Stars form Where, When, and How? ? • Implications • -evolution of galaxy’s gas & stars with time • -variety/longevity of extrasolar systems

  17. Key Questions How does the IMF vary with environment? How fast do clouds & stars form? What creates variety in “protoplanetary” disks?

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