When CDC is enabled for a database and one or more tables, an associated Change Data Capture table is created for each table being monitored. The Change Data Capture tables are used to store the changes made to the data in corresponding source tables, along with some metadata used to track the changes. By default, the name of the CDC change table is
schemaname_tablename_CT and is based on the name of the source table.
The first five columns of a Change Data Capture change table are metadata columns and contain additional information relevant to the recorded change:
_$start_lsn—Identifies the commit log sequence number ...