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

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

Mass Matters

Orion Constellation Movie

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

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

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

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

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

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

Science & Technology How Fast Do Clouds & Stars Form? Statistical analysis of large surveys at radio through X-ray wavelengths Comparison with simulations Databases of unprecedented size, and tools for retrieval, analysis & visualization. (SIRTF, COMPLETE, NVO) Simulations with high(er) dynamic range. (More powerful computers) Higher-resolution studies of disks & their environment (now: VLA, mm-interferometers & SMA; coming soon: JWST, ALMA, coming eventually, we hope: SKA) How does the IMF Vary with Environment? Comparative studies of many galactic & extragalactic star forming regions What creates variety in “protoplanetary” disks? Higher-resolution views of disks Statistical study of environmental influence

Simulated spectral-line map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan, Goodman &Juvela 2003 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 >10 4 Simulations: Including effects of gravity, magnetic fields, chemistry, heating & cooling, stars forming, & thermal pressure…but not all at once (yet) Dynamic Range <10 2

Synthetic Star Forming Regions Stone, Gammie & Ostriker 1999 Driven Turbulence; M  K; no gravity Colors: log density Computational volume: Dark blue lines: B-field Red : isosurface of passive contaminant after saturation  =0.01  =1  T /10 K  n H 2 /100 cm -3  B /1.4  G  2 Weak Magnetic Field Strong Magnetic Field

Simulations Let Us Live Longer Bate, Bonnell & Bromm 2002; c.f. Ostriker, Stone & Gammie 2001 MHD turbulence (another simulation) gives initial conditions 50 M sun, ~1 lyr, n avg =3 x 10 5 ptcls/cc forms ~50 objects T=10 K SPH, no magnetic fields or heating and cooling movie=1.4 free-fall times

Circumstellar Disks

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

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