Eight stages to the formation of a low mass star like our sun.

The Stages: 1. The Cloud: 10 pc, 104 Msun , 108 yr (supersonic)turbulence, magnetic (ambipolar) diffusion 2. The Clumps: 2-5 pc, 103 Msun, 107 yr magnetic energy, rotational braking 3. Cores: 0.1 pc, 1 Msun thermal support 4. Collapse: isothermal free-fall phase, 3 105 yr adiabatic phase, optically thick second collapse phase: dissociation of H2 5. Class 0: 104 yr mass in envelope accretion onto small core molecular jets and shocks 6. Class 1: 105 yr embedded IR source disk, outflow 7. Class 2: 106 yr IR+UV excesses atomic jets 8. Class 3: 107 yr naked, surface activity starspots, giant flares

Last Revised: 2009 November 2nd