postqueue -p | Queue ID | What does the '*' mean?

[penguin]

root@pinkie:/var/log# postqueue -p
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
808AD1858E*  459339 Wed Nov 23 17:20:37  i...@dpsdirect.us
                                         ********@brookeagent.com

2BDBF18581*  459337 Wed Nov 23 17:50:25  i...@dpsdirect.us
                                         ********@brookeagent.com





Does anyone know why these messages have a '*' after their ID?

Thank You!