Individual disks can also differ significantly from each other, and there is an overall trend that accretion rate decreases with age, reaching up to 10 −6 M ⊙ year −1 at the youngest ages (in the so-called class 0 phase in the first ~10 5 years), down to well below the standard value of 10 −8 M ⊙ year −1 .
1
—
—