AST 309 Lecture Notes - Lecture 11: Debris Disk, Eagle Nebula, Protoplanetary Disk
Document Summary
Are protostars, but we like to classify them into different groups based on their evolutionary stage. By class three, disk has started to cool out, planets beginning to form. Based on their observational properties, for the young star and its disk. Ysos have infrared excesses (above a normal stellar blackbody) due to dust in the protostellar disk. Class 0 protostar -point where collapsing core becomes a protostar. Large infalling envelope of gas dust, more mass in envelope than in protostar. But have a central object = protostar (stage 3/4 of star formation process) Emission peaks in far ir, don"t see central protostar, just the cloud and envelope. Class 1 yso - more evolved accreting protostar. Still have some envelope, later stage active mass accretion. Now more mass in central protostar than in envelope. Still have outflows and jets, maybe less collimated.
