To create a WordPress RSS feed of all posts associated with an author, you simply have to use RSS Feed URL format below:
So, if I only want to show posts by Walt Whitman, I would use the RSS feed URL shown below:
What can I do with WordPress RSS Feeds of authors?
If you have a particularly popular author, you may have subscribers that would like to be notified whenever they add posts to your website. In order to do this, you would create an automated email newsletter using MailChimp and the WordPress Author RSS feed.