The Nature of Young Solar-Type Stars

摘要: We focus in this review on the properties of optically visible, young stellar objects (YSOs). hope we will not be accused undue anthropocentric reasoning if say that these stars have an activity level compatible with their youth. Although each may display its own spectroscopic and photometric variability pattern at various wavelengths — which makes them fascinating to observe they share enough basic appear as classes stars. go through historical definitions following section. then briefly address question age; i.e., how do know are pre-main sequence stars? The rest is devoted physical picture has emerged over last decade, focusing mainly physics light variability, disk properties, accretion. In topics, emphasize areas where expect rapid progress next few years.