AUDITING in Oracle 11g database

Hi Team,

I executed the below query and got that auditing is not enabled for SYS user:

SQL> select distinct username from dba_audit_trail;

USERNAME

------------------------------

PUBUSER

STUDMX03

ASMUSER

PBUSER

AMDUSER

BACKUPADMN

PRIVUSER

SHEHAM07

IBRAAH01

MINER

OPS$DBMOMPRIMNP02

ABDUSB00

SCOTT

ORACLE_OCM

A

BOUWGD00

DBSNMP

SYSMAN

SHIRAZTEST

GARYTEST

ADMUSER

COLOWG00

Is there any other way to check if auditing facility is enable for SYS user or not.

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When I check any audit files I see the data present as below:

Audit file /primahome/u01/app/oracle/admin/dbmomprmnp02/adump/dbmomprmnp02_ora_11184_20160312233345070799143795.aud

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production