What is the life cycle of a domain name and it's expiration process?
The following graphic shows the life cycle of a typical domain registration extension (gTLD) through its active state and expiration process:
What about .au domains?
Similarly to the above graph, .au domains enter an expired state where a renewal can be processed to bring the name back to life. This expired state lasts 30 days, once the name has passed this point the name will be moved into an Expired Pending Purge state and added to the .au drop list for 24 hours before being purged into the public pool where it can then be registered again by the public.