<Tr> <Th> Star formation </Th> </Tr> <Tr> <Th> Object classes </Th> </Tr> <Tr> <Td> Interstellar medium Molecular cloud Bok globule Dark nebula Young stellar object Protostar T Tauri star Pre-main - sequence star Herbig Ae / Be star Herbig--Haro object </Td> </Tr> <Tr> <Th> Theoretical concepts </Th> </Tr>

Which mechanisms that can cause a giant molecular cloud to collapse and form a protostar