View or Terminate Root User Active Sessions

You can use Systems Manager to view information about sessions in your account.

https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager-working-with-view-history.html

According to the Console FAQ, console sessions only last 12 hours until they have to reauthenticate. So, you should be able to query the CloudTrail logs for root logins less than 12 hours.

CloudTrail records sign-in events including root's, but not sure if active session details are available anywhere.

for cloudTrail details you can check below link.

https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-event-reference-aws-console-sign-in-events.html#cloudtrail-event-reference-aws-console-sign-in-events-root

CloudTrial doesn't have anything configured.

To be specific; I'm looking to see what current sessions exist in a new account without anything configured or created.

An account was created the account on a machine that is no longer accessible. I want to either see the login activity from that machine to make sure I'm happy no-one could use the account or or at least ensure that any sessions created so far are all fully terminated.

Is there any way to do either of those options?