Add new authentication variable in Community Auth

Hi.

For application that I am developing, I want add a new authentication variable for it is available en views, controllers, etc.
Is very simple, I need have avatar's image of user that is logged in, to show it in the page, like his name or role.

I have created a new field in db table users, and when I have viewed Auth_Controller to modify it, in the property declarations, I haven't seen property $auth_email. It isn't necessary?

There are:
$auth_user_id
$auth_username
$auth_level
$auth_role

$auth_data
$acl
$protocol

But $auth_email isn't declared.
If I want add a new variable for use it before, I needn't declare it?

Thanks.