| | 183 | The paper begins by providing some background information on different phases of the pre-stellar and protostellar phases. Definitions of class 0, 1, 2 are provided as well as their relative properties (flat inner core regions, envelope properties that differ in high density star forming regions compared to more sparse regions, infall velocity maps, etc.) and lifetimes (class 0 < class I < class II)- as inferred by statistical arguments. The observations seem to tell a coherent story of star formation that is at odds with the "standard theory of star formation" of Shu, Adams, and Lizano (1987) which describes collapse as occurring by way of the similarity solution of the SIS. This standard theory then predicts a prestellar cloud that is centrally peaked and static (vrad ~ 0 for all r) that collapses from the inside out in an expansion wave. At the time of collapse, the protostar forms and accretes surrounding material at a CONSTANT rate. These predictions of the SIS similarity solution are not supported by observation. |
